• Journal of Ginseng Research
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• v.39 no.1
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• pp.54-60
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• 2015

Background: The present study was designed to prepare and find the optimum active preparation or fraction from Korea Red Ginseng inhibiting matrix metalloproteinase-13 (MMP-13) expression, because MMP-13 is a pivotal enzyme to degrade the collagen matrix of the joint cartilage. Methods: From total red ginseng ethanol extract, n-BuOH fraction (total ginsenoside-enriched fraction), ginsenoside diol-type-enriched fraction (GDF), and ginsenoside triol-type-enriched fraction (GTF) were prepared, and ginsenoside diol type-/F4-enriched fraction (GDF/F4) was obtained from Panax ginseng leaf extract. Results: The n-BuOH fraction, GDF, and GDF/F4 clearly inhibited MMP-13 expression compared to interleukin-$1{\beta}$-treated SW1353 cells (human chondrosarcoma), whereas the total extract and ginsenoside diol-type-enriched fraction did not. In particular, GDF/F4, the most effective inhibitor, blocked the activation of p38 mitogen-activated protein kinase (p38 MAPK), c-Jun-activated protein kinase (JNK), and signal transducer and activator of transcription-1/2 (STAT-1/2) among the signal transcription pathways involved. Further, GDF/F4 also inhibited the glycosaminoglycan release from interleukin-$1{\alpha}$-treated rabbit cartilage culture (30.6% inhibition at $30{\mu}g/mL$). Conclusion: Some preparations from Korean Red Ginseng and ginseng leaves, particularly GDF/F4, may possess the protective activity against cartilage degradation in joint disorders, and may have potential as new therapeutic agents.

• Biomolecules & Therapeutics
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• v.29 no.1
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• pp.90-97
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• 2021

Ultraviolet B (UVB) radiation causes DNA base modifications. One of these changes leads to the generation of 8-oxoguanine (8-oxoG) due to oxidative stress. In human skin, this modification may induce sunburn, inflammation, and aging and may ultimately result in cancer. We investigated whether phloroglucinol (1,3,5-trihydroxybenzene), by enhancing the expression and activity of 8-oxoG DNA glycosylase 1 (Ogg1), had an effect on the capacity of UVB-exposed human HaCaT keratinocytes to repair oxidative DNA damage. Here, the effects of phloroglucinol were investigated using a luciferase activity assay, reverse transcription-polymerase chain reactions, western blot analysis, and a chromatin immunoprecipitation assay. Phloroglucinol restored Ogg1 activity and decreased the formation of 8-oxoG in UVB-exposed cells. Moreover, phloroglucinol increased Ogg1 transcription and protein expression, counteracting the UVB-induced reduction in Ogg1 levels. Phloroglucinol also enhanced the nuclear translocation of nuclear factor erythroid 2-related factor 2 (Nrf2) as well as Nrf2 binding to an antioxidant response element located in the Ogg1 gene promoter. UVB exposure inhibited the phosphorylation of protein kinase B (PKB or Akt) and extracellular signal-regulated kinase (Erk), two major enzymes involved in cell protection against oxidative stress, regulating the activity of Nrf2. Akt and Erk phosphorylation was restored by phloroglucinol in the UVB-exposed keratinocytes. These results indicated that phloroglucinol attenuated UVB-induced 8-oxoG formation in keratinocytes via an Akt/Erk-dependent, Nrf2/Ogg1-mediated signaling pathway.

• Journal of Microbiology and Biotechnology
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• v.31 no.7
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• pp.912-920
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• 2021

SOS response is a conserved response to DNA damage in prokaryotes and is negatively regulated by LexA protein, which recognizes specifically an "SOS-box" motif present in the promoter region of SOS genes. Myxococcus xanthus DK1622 possesses a lexA gene, and while the deletion of lexA had no significant effect on either bacterial morphology, UV-C resistance, or sporulation, it did delay growth. UV-C radiation resulted in 651 upregulated genes in M. xanthus, including the typical SOS genes lexA, recA, uvrA, recN and so on, mostly enriched in the pathways of DNA replication and repair, secondary metabolism, and signal transduction. The UV-irradiated lexA mutant also showed the induced expression of SOS genes and these SOS genes enriched into a similar pathway profile to that of wild-type strain. Without irradiation treatment, the absence of LexA enhanced the expression of 122 genes that were not enriched in any pathway. Further analysis of the promoter sequence revealed that in the 122 genes, only the promoters of recA2, lexA and an operon composed of three genes (pafB, pafC and cyaA) had SOS box sequence to which the LexA protein is bound directly. These results update our current understanding of SOS response in M. xanthus and show that UV induces more genes involved in secondary metabolism and signal transduction in addition to DNA replication and repair; and while the canonical LexA-dependent regulation on SOS response has shrunk, only 5 SOS genes are directly repressed by LexA.

• Molecules and Cells
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• v.45 no.8
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• pp.537-549
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• 2022

Preproenkephalin (PPE) is a precursor molecule for multiple endogenous opioid peptides Leu-enkephalin (ENK) and Met-ENK, which are involved in a wide variety of modulatory functions in the nervous system. Despite the functional importance of ENK in the brain, the effect of brain-derived factor(s) on PPE expression is unknown. We report the dual effect of neural epidermal growth factor (EGF)-like-like 2 (NELL2) on PPE gene expression. In cultured NIH3T3 cells, transfection of NELL2 expression vectors induced an inhibition of PPE transcription intracellularly, in parallel with downregulation of protein kinase C signaling pathways and extracellular signal-regulated kinase. Interestingly, these phenomena were reversed when synthetic NELL2 was administered extracellularly. The in vivo disruption of NELL2 synthesis resulted in an increase in PPE mRNA level in the rat brain, suggesting that the inhibitory action of intracellular NELL2 predominates the activation effect of extracellular NELL2 on PPE gene expression in the brain. Biochemical and molecular studies with mutant NELL2 structures further demonstrated the critical role of EGF-like repeat domains in NELL2 for regulation of PPE transcription. These are the first results to reveal the spatio-specific role of NELL2 in the homeostatic regulation of PPE gene expression.

• Journal of the Institute of Convergence Signal Processing
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• v.23 no.3
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• pp.137-142
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• 2022

Every year, the number of wild animals appearing in human settlements increases, resulting in increased damage to property and human life. In particular, the damage is more severe when wild animals appear on highways or farmhouses. To solve this problem, ecological pathways and guide fences are being installed on highways. In addition, in order to solve the problem in farms, horn repelling using sensors, installing a net, and repelling by smell of excrement are being used. However, these methods are expensive and their effectiveness is not high. In this paper, we used YOLO (You Only Look Once), an AI-based image analysis method, to analyze harmful animals in real time to reduce malfunctions, and high-brightness LEDs and ultrasonic frequency speakers were used as extermination devices. The speaker outputs an audible frequency that only animals can hear, increasing the efficiency to only exterminate wild animals. The proposed system is designed using a general-purpose board so that it can be installed economically, and the detection performance is higher than that of the devices using the existing sensor.

• Journal of Ginseng Research
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• v.47 no.3
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• pp.420-428
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• 2023

Background: Ginsenoside F2 (GF2), a minor component of Panax ginseng, has been reported to possess a wide variety of pharmacological activities. However, its effects on glucose metabolism have not yet been reported. Here, we investigated the underlying signaling pathways involved in its effects on hepatic glucose. Methods: HepG2 cells were used to establish insulin-resistant (IR) model and treated with GF2. Cell viability and glucose uptake-related genes were also examined by real-time PCR and immunoblots. Results: Cell viability assays showed that GF2 up to 50 μM did not affect normal and IR-HepG2 cell viability. GF2 reduced oxidative stress by inhibiting phosphorylation of the mitogen-activated protein kinases (MAPK) signaling components such as c-Jun N-terminal kinase (JNK), extracellular signal-regulated kinase 1/2 (ERK1/2), and p38 MAPK, and reducing the nuclear translocation of NF-κB. Furthermore, GF2 activated PI3K/AKT signaling, upregulated the levels of glucose transporter 2 (GLUT-2) and GLUT-4 in IR-HepG2 cells, and promoted glucose absorption. At the same time, GF2 reduced phosphoenolpyruvate carboxykinase and glucose-6-phosphatase expression as well as inhibiting gluconeogenesis. Conclusion: Overall, GF2 improved glucose metabolism disorders by reducing cellular oxidative stress in IR-HepG2 cells via MAPK signaling, participating in the PI3K/AKT/GSK-3β signaling pathway, promoting glycogen synthesis, and inhibiting gluconeogenesis.

• The Korean Journal of Mycology
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• v.46 no.2
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• pp.161-176
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• 2018

Fungal ${\beta}$-glucan, known to have immunostimulatory and antitumor activities, can be recognized by host immune cells as one of the pathogen-associated molecular patterns (PAMPs). Although there are several reports on the diverse immunostimulatory activities of ${\beta}$-glucan, little is known about the intracellular signal transduction of ${\beta}$-glucan. Stimulation of RAW264.7 macrophage cells with ${\beta}$-glucan from Ganoderma lucidum induced the expressions of dectin-1, toll-like receptor 2 (TLR2), TLR4, and TLR6 at the transcription stage. Treatment with ${\beta}$-glucan also induced inflammatory mediators such as macrophage inflammatory proteins (MIP)-$1{\alpha}$, MIP-$1{\beta}$, MIP-$1{\gamma}$, interleukin (IL)-$1{\beta}$, and tumor necrosis factor (TNF)-${\alpha}$. Treatment of the cells with polymyxin B, an inhibitor of lipopolysaccharides (LPS), blocked the induction of inflammatory mediators in LPS- or ${\beta}$-glucan-stimulated systems. Pretreatment of the cells in our cell culture system with LY294002, a phosphoinositide 3-kinase (PI3K) inhibitor, or U0126, a mitogen-activated protein kinase/extracellular-signal-regulated kinase (MAPK/ERK) kinase (MEK)1/MEK2 inhibitor, led to a reduction in the induction of inflammatory mediators in a concentration-dependent manner. These results show that stimulation of the macrophage cells by ${\beta}$-glucan induced the expressions of both dectin-1 and TLRs. We also found that the PI3K/Akt and MEK pathways were involved in the induction of inflammatory mediators in macrophage cells during intracellular signal transduction of ${\beta}$-glucan.

• Animal cells and systems
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• v.2 no.1
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• pp.87-91
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• 1998

The present study investigated the involvement of the phospholipase C (PLC) and protein kinase C (PKC) signaling pathways during progesteroneinduced meiotic maturation in amphibian (Rana dybowskii) oocytes. Prosesterone-induced germinal vesicle breakdown (GVBD) of oocytes was significantly inhibited by a PKC inhibitor, staurosporine and a PLC inhibitor, U73122, in a dose-dependent manner. In contrast, U73343, an inactive analogue of U73122, was ineffective in suppressing GVBD. PKC activity in oocytes reached a maximum level at 30 min after progesterone stimulation and this elevated PKC activity was effectively suppressed by U73122 or staurosporine, suggesting that the activation of PKC enzyme is closely linked to PLC signaling during oocyte maturation. In addition, these inhib itors blocked the maturation promoting factor (MPF) activity which appeared in oocytes in response to progesterone, suggesting that PKC activation is an important signal for MPF activity. Therefore, this study demonstrates that the activation of PKC via PLC signaling is directly linked to an intracellular protein kinase cascade related to the appearance of MPF activity during meiotic maturation in amphibian (Rana dybowskii) oocytes.

• Biotechnology and Bioprocess Engineering:BBE
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• v.7 no.5
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• pp.237-251
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• 2002

The recent progress on metabolic systems engineering was reviewed based on our recent research results in terms of (1) metabolic signal flow diagram approach, (2) metabolic flux analysis (MFA) in particular with intracellular isotopomer distribution using NMR and/or GC-MS, (3) synthesis and optimization of metabolic flux distribution (MFD), (4) modification of MFD by gene manipulation and by controlling culture environment, (5) metabolic control analysis (MCA), (6) design of metabolic regulation structure, and (7) identification of unknown pathways with isotope tracing by NMR. The main characteristics of metabolic engineering is to treat metabolism as a network or entirety instead of individual reactions. The applications were made for poly-3-hydroxybutyrate (PHB) production using Ralstonia eutropha and recombinant Escherichia coli, lactate production by recombinant Saccharomyces cerevisiae, pyruvate production by vitamin auxotrophic yeast Toluropsis glabrata, lysine production using Corynebacterium glutamicum, and energetic analysis of photosynthesic microorganisms such as Cyanobateria. The characteristics of each approach were reviewed with their applications. The approach based on isotope labeling experiments gives reliable and quantitative results for metabolic flux analysis. It should be recognized that the next stage should be toward the investigation of metabolic flux analysis with gene and protein expressions to uncover the metabolic regulation in relation to genetic modification and/ or the change in the culture condition.

• Molecules and Cells
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• v.26 no.5
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• pp.481-485
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• 2008

As an inhibitor of phosphatidylcholine-specific phospholipase C (PC-PLC), D609 has been widely used to explain the role of PC-PLC in various signal transduction pathways. This study shows that D609 inhibits group IV cytosolic phospholipase $A_2$ ($cPLA_2$), but neither secretory $PLA_2$ nor a $Ca^{2+}$-dependent $PLA_2$. Dixon plot analysis shows a mixed pattern of noncompetitive and uncompetitive inhibition with $K_i=86.25{\mu}M$ for the $cPLA_2$ purified from bovine spleen. D609 also time- and dose-dependently reduces the release of arachidonic acid from a $Ca^{2+}$- ionophore A23187-stimulated MDCK cells. In the AA release experiment, $IC_{50}$ of D609 was ${\sim375}{\mu}M$, suggesting that this reagent may not enter the cells easily. The present study indicates that the inhibitory effects of D609 on various cellular responses may be partially attributable to the inhibition of $cPLA_2$.