• Molecules and Cells
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• v.37 no.10
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• pp.734-741
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• 2014

Histone modifications on major transcription factor target genes are one of the major regulatory mechanisms controlling adipogenesis. Plant homeodomain finger 2 (PHF2) is a Jumonji domain-containing protein and is known to demethylate the histone H3K9, a repressive gene marker. To better understand the function of PHF2 in adipocyte differentiation, we constructed stable PHF2 knock-down cells by using the mouse pre-adipocyte cell line 3T3-L1. When induced with adipogenic media, PHF2 knock-down cells showed reduced lipid accumulation compared to control cells. Differential expression using a cDNA microarray revealed significant reduction of metabolic pathway genes in the PHF2 knock-down cell line after differentiation. The reduced expression of major transcription factors and adipokines was confirmed with reverse transcription- quantitative polymerase chain reaction and Western blotting. We further performed co-immunoprecipitation analysis of PHF2 with four major adipogenic transcription factors, and we found that CCATT/enhancer binding protein (C/EBP)${\alpha}$ and C/EBP${\delta}$ physically interact with PHF2. In addition, PHF2 binding to target gene promoters was confirmed with a chromatin immunoprecipitation experiment. Finally, histone H3K9 methylation markers on the PHF2-binding sequences were increased in PHF2 knock-down cells after differentiation. Together, these results demonstrate that PHF2 histone demethylase controls adipogenic gene expression during differentiation.

• The Korea Journal of Herbology
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• v.35 no.4
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• pp.9-16
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• 2020

Objective : To identify the effects of the water extract of Liriope platyphylla tuber (Liriopis tuber, LT) on the activation of astocytes, we investigated the regulatory effects of LT extract on H₂O₂-induced oxidative damage in C6 rat astrocytes. Methods : LT extract was extracted with boiling water. C6 cell line were treated with LT extract at 1, 2, and 3 mg/㎖ or without for 30 min and then stimulated with H₂O₂ at 5 ㎛ for 24 hr. The cell viability was measured by MTT assay. The expression of glial fibrillary acidic protein (GFAP), signal transducer and activator of transcription 3 (STAT3), phospho-STAT3 (pSTAT3), cyclooxygenase (COX-2), Nuclear factor-κB (NF-κB), superoxide dismutase 2 (SOD2), heme oxygenase-1 (HO-1), catalase, Akt, phospho-Akt (p-Akt) phosphoinositide 3-kinases (PI3K), and protein kinase C alpha (PKCα) proteins were determined by Western blot, respectively. GFAP expression was also observed with immunocytochemistry under a fluorescence microscope. Results : LT extract induced cell proliferation in H₂O₂-stimulated C6 cells. LT extract significantly inhibited the expression of GFAP, NF-κB and COX-2 and increased the expression of HO-1 and the phosphorylation of STAT3 in H₂O₂-stimulated C6 cells. LT extract also significantly increased the phosphorylation of Akt and decreased the expression of PKCα in a dose-dependent manner in H₂O₂-stimulated C6 cells. Conclusions : LT extract can regulate H₂O₂-induced activation of astrocytes through inhibiting the expression of NF-κB, COX-2 and regulating Akt / HO-1, STAT3 or PKCα signaling pathway.

• The Korean Journal of Physiology and Pharmacology
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• v.9 no.4
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• pp.195-201
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• 2005

High extracellular glucose concentration was reported to suppress intracellular $Ca^{2+}$ clearing through altered sarcoplasmic reticulum (SR) function. In the present study, we attempted to elucidate the effects of pyruvate and fatty acid on SR function and reveal the mechanistic link with glucose-induced SR dysfunction. For this purpose, SR $Ca^{2+}$-uptake rate was measured in digitonin-permeabilized H9c2 cardiomyocytes cultured in various conditions. Exposure of these cells to 5 mM pyruvate for 2 days induced a significant suppression of SR $Ca^{2+}$-uptake, which was comparable to the effects of high glucose. These effects were accompanied with decreased glucose utilization. However, pyruvate could not further suppress SR $Ca^{2+}$-uptake in cells cultured in high glucose condition. Enhanced entry of pyruvate into mitochondria by dichloroacetate, an activator of pyruvate dehydrogenase complex, also induced suppression of SR $Ca^{2+}$-uptake, indicating that mitochondrial uptake of pyruvate is required in the SR dysfunction induced by pyruvate or glucose. On the other hand, augmentation of fatty acid supply by adding 0.2 to 0.8 mM oleic acid resulted in a dose-dependent suppression of SR $Ca^{2+}$-uptake. However, these effects were attenuated in high glucose-cultured cells, with no significant changes by oleic acid concentrations lower than 0.4 mM. These results demonstrate that (1) increased pyruvate oxidation is the key mechanism in the SR dysfunction observed in high glucose-cultured cardiomyocytes; (2) exogenous fatty acid also suppresses SR $Ca^{2+}$-uptake, presumably through a mechanism shared by glucose.

• Journal of Photoscience
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• v.9 no.2
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• pp.86-89
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• 2002

Blue light activates proton pump, and creates electrical gradient across the plasma membrane and drives $K^{+}$ uptake in stomatal guard cells. In this presentation, we provide evidence for regulatory mechanisms of the pump and the identification of blue light receptor. The pump is shown to be the plasma membrane H$^{+}$- ATPase and is activated through phosphorylation of the C-terminus. Phosphorylation occurred and 14-3-3 protein bound to the phosphorylation site. The binding of 14-3-3 protein was required for the H$^{+}$-ATPase activation. We also found that phot1 phot2 double mutant does not respond to blue light but other mutants respond to blue light by stomatal opening. However, all these mutants are capable of stomatal opening in the presence of fusicoccin, an activator of the H$^{+}$-ATPase. These results suggest that both photl and phot2 act as blue light receptors in guard cells.d cells.

• Microbiology and Biotechnology Letters
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• v.19 no.4
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• pp.390-397
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• 1991

Ethanol production by calcium alginate-immobilized baker's yeast (Saccharor/tyces cereviszae) was studied in the batch fermentation using glucose medium as a feed. Immobilied cells were stable between $30^{\circ}C$ and $40^{\circ}C$ whereas free cells were stable between $30^{\circ}C$ and $37^{\circ}C$ The beads were showed constant ethanol productivity during 720 hours (30 days) over. Fermentation characteristics of immobilized baker's yeast were examined changing the initial glucose concentration of broth in fermentation. Initial glucose concentrations employed were 50, 100, 150 and 200 g/l, respectively. In 15% gucose medium, maximum specific growth rate, maximum ethanol yield and ethanol concentration were observed as 0.092 $h^{-1}$, 0.45, 67.5 g/l, respectively.

• IMMUNE NETWORK
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• v.4 no.4
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• pp.229-236
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• 2004

Background: Disialoganglioside GD2 is a tumor-associated antigen that is overexpressed on tumor cells of neuroectodermal origin, such as melanoma, small cell lung carcinoma and neuroblastoma. Immunity against GD2 has anti-tumor activities, but GD2 is poorly immunogenic. Anti-idiotypic antibodies that mimic GD2 may induce more effective immune responses than GD2 antigen itself, because they are protein antigens and are known to be able to break immune tolerance. In our previous study, we produced anti-idiotypic antibodies mimicking GD2 (3A4 and 3H9), which induced humoral immunity. However, cellular immunity is essential to eradicate tumor cells in vivo as well as humoral immunity. In the present study, we investigated whether these anti-idiotypic antibodies 3A4 and 3H9 could induce cellular immunes responses. Methods: BALB/C mice were immunized with anti-idiotypic antibody 3A4 or 3H9, or normal mouse IgG as a negative control. Lymphoproliferative responses, cytokine production responses, and delayed-type hypersensitivity reactions were measured in mice immunized with the anti-idiotypic antibodies. Results: Both the anti-idiotypic antibody 3A4 and 3H9 induced GD2-specific lymphoproliferative responses and $IFN-{\gamma}$ production of lymph node lymphocytes in BALB/C mice. Only anti-idiotypic antibody 3H9 induced significant GD2-specific delayed-type hypersensitivity in the mice. Conclusion: These results show that anti-idiotypic antibodies 3A4 and 3H9 have the potentiality of inducing GD2-specific cellular immune responses that cannot be induced by the native antigen GD2 itself.

• Journal of Microbiology and Biotechnology
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• v.25 no.3
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• pp.413-417
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• 2015

Recently, we isolated HY253, a novel decahydrofluorene analog with a molecular structure of 7,8a-divinyl-2,4a,4b,5,6,7,8,8a,9,9a-decahydro-1H-fluorene-2,4a,4b,9a-tetraol from the roots of Aralia continentalis, which is known as Dokwhal (獨活), a traditional medicinal herb. Moreover, we previously reported its cytotoxic activity on cancer cell proliferation in human lung cancer A549 and cervical cancer HeLa cells. The current study aimed to evaluate its detailed molecular mechanisms in cell cycle arrest and apoptotic induction in human hepatocellular carcinoma HepG2 cells. Flow cytometric analysis of HepG2 cells treated with $60{\mu}M$ HY253 revealed appreciable cell cycle arrest at the G1 phase via inhibition of Rb phosphorylation and down-regulation of cyclin D1. Furthermore, using western blots, we found that up-regulation of cyclin-dependent kinase inhibitors, such as p21^CIP1 and p27^KIP1, was associated with this G₁ phase arrest. Moreover, TUNEL assay and immunoblottings revealed apoptotic induction in HepG2 cells treated with $60{\mu}M$ HY253 for 24 h, which is associated with cytochrome c release from mitochondria, via down-regulation of anti-apoptotic Bcl-2 protein, which in turn resulted in activation of caspase-9 and -3, and proteolytic cleavage of poly(ADP-ribose) polymerase (PARP). Accordingly, we suggest that HY253 may be a potent chemotherapeutic hit compound for treating human liver cancer cells via up-regulation and activation of the p53 gene.

• Microbiology and Biotechnology Letters
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• v.43 no.2
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• pp.134-141
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• 2015

An agarolytic marine bacterium (H9) was isolated from the coastal seawater of the West Sea, South Korea. The isolate, H9, was gram-negative and rod-shaped with a smooth surface and polar flagellum. Cells grew at 20-30℃, between pH 5.0 and 9.0, and in ASW-YP (Artificial Sea Water-Yeast extract, Peptone) media containing 1-5% (w/v) NaCl. The G+C content was 41.56 mol%. The predominant isoprenoid quinone in strain H9 was ubiquinone-8. The major fatty acids (>10%) were C_16:1ω7c (34.3%), C_16:0 (23.72%), and C_18:1ω7c (13.64%). Based on 16S rRNA gene sequencing, and biochemical and chemotaxonomic characterization, the strain was designated as Pseudoalteromonas sp. H9 (=KCTC23887). In liquid culture supplemented with 0.2% agar, the cell density and agarase activity reached a maximum level of OD = 4.32 (48 h) and OD = 3.87 (24 h), respectively. The optimum pH and temperature for the extracellular crude agarases of H9 were 7.0 and 40℃, respectively. Thin-layer chromatography analysis of the agarase hydrolysis products revealed that the crude agarases hydrolyze agarose into neoagarotetraose and neoagarohexaose. Therefore, the new agar-degrading strain, H9, can be applicable for the production of valuable neoagarooligosaccharides and for the complete degradation of agar in bio-industries.

• Molecules and Cells
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• v.42 no.5
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• pp.397-405
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• 2019

The regulatory role of long noncoding RNA (lncRNA) growth arrest-specific transcript 5 (GAS5) in both cancerous and noncancerous cells have been widely reported. This study aimed to evaluate the role of lncRNA GAS5 in heart failure caused by myocardial infarction. We reported that silence of lncRNA GAS5 attenuated hypoxia-triggered cell death, as cell viability was increased and apoptosis rate was decreased. This phenomenon was coupled with the down-regulated expression of p53, Bax and cleaved caspase-3, as well as the up-regulated expression of CyclinD1, CDK4 and Bcl-2. At the meantime, the expression of four heart failure-related miR-NAs was altered when lncRNA GAS5 was silenced (miR-21 and miR-142-5p were up-regulated; miR-30b and miR-93 were down-regulated). RNA immunoprecipitation assay results showed that lncRNA GAS5 worked as a molecular sponge for miR-142-5p. More interestingly, the protective actions of lncRNA GAS5 silence on hypoxia-stimulated cells were attenuated by miR-142-5p suppression. Besides, TP53INP1 was a target gene for miR-142-5p. Silence of lncRNA GAS5 promoted the activation of PI3K/AKT and MEK/ERK signaling pathways in a miR-142-5p-dependent manner. Collectively, this study demonstrated that silence of lncRNA GAS5 protected H9c2 cells against hypoxia-induced injury possibly via sponging miR-142-5p, functionally releasing TP53INP1 mRNA transcripts that are normally targeted by miR-142-5p.

• The Journal of Korean Medicine
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• v.22 no.4
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• pp.45-57
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• 2001

Objectives : The water extract of Gwibitang (GBT) has been traditionally used for treatment of psychologic disease and brain damage in Oriental Medicine, This study was designed to investigate the effect of GBT on the glutamate-induced toxicity of rat C6 glial cells. Methods : The cultured cells were pretreated with GBT and exposed to glutamate, The cell damage was assessed by using MTT assay and Hoechst, IC-l staining, Results : GBT had protective effects in glutamate-induced cytotoxicity, which was revealed as apoptosis characterized by chromatic condensation and the loss of mitochondrial membrane potential in C6 glial cells. However, GBT and glutamate had no effect in the activation of caspase family cysteine proteases including caspase-3, -8 and -9 proteasesin C6 glial ce]]s, GBT significantly recovered the depletion of GSH and inhibited the generation of $H_2O_2$ by glutamate in C6 glial cells. In addition, both GBT and antioxidants such as GSH and NAC protected the glutamate-induced cytotoxicity in C6 glial cells, indicating that GBT possibly has antioxidative effect. Moreover, GBT also inhibited the glutamate-induced degradation of $IkB{\alpha}$ in C6 glial cells, This result suggest that GBT has some inhibitory effects on the transcriptional activation of $NF-_{k}B$. Conclusions : GBT has protective effects in glutamate-induced cytotoxicity via an antioxidative mechanism.