• Environmental Mutagens and Carcinogens
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• 제25권1호
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• pp.19-24
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• 2005

The Swedish double mutation (KM670/671NL) of amyloid precursor protein (Swe-APP) is associated with early-onset familial Alzheimer's disease (FAD) and increases amyloid beta peptide production. Although APP/A/3 mediated neurotoxicity is observed both in vitro and in vivo, the relationship between mutant APP expression, A/3 production, and neuronal death observed in the brains of FAD patients remains to be elucidated. In this study, we investigated the mechanisms of Swe-APP-induced cell death in HEK293 and NGF-differentiated PC 12 cells. We found that the expression of Swe-APP induced cytochrome C relase, activation of caspase 3 in HEK 293 and NGF-differentiated PC 12 cells. We also show that the reactive oxygen species (ROS) was detected in Swe-APP expressing HEK 293 cells and NGF-differentiated PC 12 cells and that pretreatment with vitamine E attenuated the cellular death, cytochrome C release induced by Swe-APP expression, indicating the involvement of free radical in these processes. These results suggest one of possible apoptotic mechanisms of Swe-APP which could occur through cytochrome C release from mitochondria and this apoptosis inducing effects could be at least in part, due to ROS generation by Swe-APP expression.

• Molecules and Cells
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• 제19권2호
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• pp.289-293
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• 2005

BAF53 is an actin-related protein that shuttles between nucleus and cytoplasm. In the nucleus, it constitutes an integral component of many chromatin-modifying complexes such as the SWI/SNF, TIP60, TRRAP, and TIP48/49 complexes. BAF53 is essential for growth, but its function remains elusive. BAF53 homologues from yeast to humans have a conserved N-terminal motif, MS_(G/A)(G/A)__(V/L)YGG, which is unique to these proteins. Previously we showed that over-expression of an N-terminal deletion mutant of BAF53 ($BAF53_-{\Delta}N$) reduced the viability of HEK293 and HeLa cells. When we replaced the serine 2 and tyrosine 6 of this N-terminal motif with alanine, over-expression of the alanine-replaced BAF53 strongly impaired the growth of HEK293 cells whereas replacement with aspartate/glutamate had no effect. The alanine-replaced BAF53 mutants also stimulated p53-dependent transcription, in which the SWI/SNF and TRRAP complexes are involved. Our results demonstrate that serine 2 and tyrosine 6 play important roles in BAF53 activity.

• International Journal of Oral Biology
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• 제33권1호
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• pp.1-5
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• 2008

Adenosine 5'-triphosphate (ATP) is an important extracellular signaling molecule which is involved in a variety of physiological responses in many different tissues and cell types, by acting at P2 receptors, either ionotropic (P2X) or G protein-coupled metabotropic receptors (P2Y). P2X receptors have seven isoforms designated as $P2X_{1^-}P2X_7$. In this study, we investigated the electrophysiological and pharmacological properties of rat $P2X_{1^-}P2X_4$ currents by using whole-cell patch clamp technique in a heterologous expression system. When ATP-induced currents were analyzed in human embryonic kidney (HEK293) cells following transient transfection of rat $P2X_{1^-}P2X_4$, the currents showed different pharmacological and electrophysiological properties. ATP evoked inward currents with fast activation and fast desensitization in $P2X_{^1-}$ or $P2X_{3^-}$ expressing HEK293 cells, but in $P2X_{2^-}$ or $P2X_{4^-}$ expressing HEK293 cells, ATP evoked inward currents with slow activation and slow desensitization. While PPADS and suramin inhibited $P2X_2$ or $P2X_3$ receptor-mediated currents, they had little effects on $P2X_4$ receptor-mediated currents. Ivermectin potentiated and prolonged $P2X_4$ receptor-mediated currents, but did not affect $P2X_2$ or $P2X_3$ receptor-mediated currents. We suggest that distinct pharmacological and electrophysiological properties among P2X receptor subtypes would be a useful tool to determine expression patterns of P2X receptors in the nervous system including trigeminal sensory neurons and microglia.

• The Transactions of The Korean Institute of Electrical Engineers
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• 제56권12호
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• pp.2208-2213
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• 2007

In this study we have developed a hyperspectrum imaging system for highly sensitive and effective imaging analysis. An optical setup was designed using acoustic optical tunable filter (AOTF) for high sensitive hyperspectrum imaging. Light emitted by mercury lamp gets split in to diffracted and undiffracted beams while passing though AOTF. GFP transfected HEK-293 cell line was used as a model for in vitro imaging analysis. Cells were first, analyzed by fluorescence microscope followed by flow cytometric analysis. Flow cytometric analysis showed 66.31% transfection yield in GFP transfected HEK-293 cells. Various images of GFP transfected HEK-293 cell were grabbed by collecting the diffracted light using a CCD over a dynamic range of frequency of 129-171 MHz with an interval of 3 MHz. Subsequently, for in vivo image analysis of GFP transfected cells in mouse, a whole-body-imaging system was constructed. The blue light of 488 nm wavelength was obtained from a Xenon arc lamp using an appropriate filter and transmitted through an optical cable to a ring illuminator. To check the efficacy of the newly developed whole-body-imaging system, a comparative imaging analysis was performed on a normal mouse in presence and absence of Xenon arc irradiation. The developed hyperspectrum imaging analysis with AOTF showed the highest intensity of green fluorescent protein at 153 MHz of frequency and 494 nm of wavelength. However, the fluorescence intensity remained same as that of the background below 138 MHz (475 nm) and above 162 MHz (532 nm). The mouse images captured using the constructed whole-body-imaging system appeared monochromatic in absence of Xenon arc irradiation and blue when irradiated with Xenon arc lamp. Nevertheless, in either case mouse images appeared clearly.

• Carbon letters
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• 제17권1호
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• pp.45-52
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• 2016

The attachment of 2-aminobenzamide to carboxylated multi-wall carbon nanotubes (MWCNTs)-COOH was achieved through the formation of amide bonds. Then, the functionalized MWCNTs, MWCNT-amide, were treated by phosphoryl chloride to produce MWCNT-quin. The products were characterized by Fourier transform infrared spectroscopy, Raman spectroscopy, scanning electron microscopy, thermogravimetric analysis, derivative thermogravimetric, steady-state fluorescence spectroscopy, and solubility testing. MWCNT-quin showed photo-electronic properties, which is due to the attachment of the 4-hydroxyquinazoline groups to them as proved by steady-state fluorescence spectroscopy. This suggests intramolecular interactions between the tubes and the attached 4-hydroxyquinazoline. The toxicity of the samples was evaluated in human embryonic kidney HEK293 and human breast cancer SKBR3 cell lines, and the viable cell numbers were measured by 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyltetrazolium bromide (MTT) after the cells were cultured for 24 h. Cellular investigations showed that the modified MWCNTs, particularly MWCNT-quin, have considerably significant toxic impact on SKBR3 as compared to HEK293 at the concentration of 5 µg/mL.

• Journal of the Korea Academia-Industrial cooperation Society
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• 제16권11호
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• pp.7575-7581
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• 2015

Corticotropin-releasing factor(CRF), one of the stress driven neuropeptides, was widely proposed to influence hair loss and re-growth. For the development of receptor antagonists, the screening system based on intracellular calcium signal process was developed and optimized. The aequorin parental cells were transfected with CRF1 receptor and alpha 16 promiscuous G protein cDNA to establish HEK293a16/hCRF1, a stable cell line for the human CRF1 receptor. In HEK293a16/hCRF1 cells, the range of sauvagine dose response was 12-fold higher($EC_{50}:15.21{\pm}1.83nM$) than in the transiently expressed cells, hence essential conditions for the antagonist screening experiments such as the robust signals and high solvent tolerance were secured. The standard antagonists for the CRF1 receptor, antalarmin and CP154526, resulted $IC_{50}$ values of $414.1{\pm}5.5$ and $290.7{\pm}1.9nM$, respectively. Similar results were presented with frozen HEK293a16/hCRF1 cells. Finally, our HEK293a16/hCRF1 cells with the aequorin based cellular functional assay can be a model system for the development of functional cosmetics and modulators that can have a clinical efficacy on hair re-growth.

• Animal cells and systems
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• 제16권5호
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• pp.376-384
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• 2012

Although ginsenosides have a variety of physiologic or pharmacologic functions in various regions, there are only a few reports on the effects of transient receptor potential melastatin 7 (TRPM7) channels. Here, we showed evidence suggesting that TRPM7 channels play an important role in ginseng total saponin (GTS)-mediated cellular injury. The combination techniques of electrophysiology, pharmacological analysis, small interfering RNA (siRNA) method and cell death assays were used. GTS depolarized the resting membrane potentials and decreased the amplitude of pacemaker potentials in cultured interstitial cells of Cajal (ICCs) in gastrointestinal (GI) tract. The TRPM7-like currents in single ICCs and the overexpressing TRPM7 in HEK293 cells were inhibited by GTS. However, GTS had no effect on $Ca^{2+}$-activated $Cl^-$ conductance. GTS inhibited the survival of human gastric (AGS) and brea (MCF-7) adenocarcinoma cells. Also, GTS inhibited the TRPM7-like currents in AGS and MCF-7 cells. The GTS-mediated cytotoxicity was inhibited by TRPM7-specific siRNA. In addition, we showed that overexpression of TRPM7 channels in HEK293 cells was inhibited by GTS. Thus, TRPM7 channels are involved in GTS-mediated cell death in AGS and MCF-7 cells, and these channels may represent a novel target for physiological disorders where GTS plays an important role.

• Proceedings of the Korean Vacuum Society Conference
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• 한국진공학회 2013년도 제45회 하계 정기학술대회 초록집
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• pp.266.2-266.2
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• 2013

According to advanced nanotechnology, the nanostructured materials with various kinds and shape are synthesized easily or produced by process. Recently, researches about interaction between the nanostructured materials and biological system have been progressed actively. The surface topography may influence cellular responses, for example cell adhesion, cell morphology. In this work, we synthesized vertically aligned silicon nanowires (SiNWs) on the Au-covered Si(111) wafer by chemical vapor deposition (CVD) method. We accomplished to control of the SiNWs diameter by regulating thickness of Au film such as 1 nm and 10 nm. These substrates did not isolate cells and just provided surface topography for cell culture. Human Embryonic Kidney 293T cells (HEK 293T cells) were cultured on these substrates for 2 days. We studied the nanotopographical effects on cell morphology, adhesion, and growth which are evaluated on each SiNWs substrate comparing bare glass as control.

• Journal of Microbiology and Biotechnology
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• 제17권1호
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• pp.154-161
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• 2007

Human immunodeficiency virus type 1 (HIV-1) infections are responsible for a substantial number of deaths annually and represent a significant threat to public health. According to the latest study, the Tat (Transactivator of transcription) protein is essential in transcription and replication of viral genes, and is among the early expression genes involved in the life cycle of HIV. The virion NC (nucleocapsid) plays an important role in early mRNA expression and contributes to the rapid viral replication that occurs during HIV-1 infection. Therefore, we attempted to elucidate the relationship between the Tat protein and nucleocapsid protein. In a comparison of two independently prepared and hybridized samples, flag NC overexpressed HEK 293T cells and pTat overexpressed HEK 293T cells, and hybridization showed the differences in expression in each case. Among the microarray results confirmed with real-time reverse transcriptase assay, twelve genes were identified to be involved according to their gene expression profiles. Of approximately 8,208 human genes that were analyzed, we monitored candidate genes that might have been related to NC and Tat genes from gene expression profiles. Additionally, the pathways could be viewed and analyzed through the use of Pathway Studio software. The pathways from the gene list were built and paths were found among the molecules/cell objects/processes by the curation method.

• The Korean Journal of Physiology and Pharmacology
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• 제12권6호
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• pp.315-321
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• 2008

Eugenol is widely used in dentistry to relieve pain. We have recently demonstrated voltage-gated $Na^+$ and $Ca^{2+}$ channels as molecular targets for its analgesic effects, and hypothesized that eugenol acts on $P2X_3$, another pain receptor expressed in trigeminal ganglion (TG), and tested the effects of eugenol by whole-cell patch clamp and $Ca^{2+}$ imaging techniques. In the present study, we investigated whether eugenol would modulate 5'-triphosphate (ATP)-induced currents in rat TG neurons and $P2X_3$-expressing human embryonic kidney (HEK) 293 cells. ATP-induced currents in TG neurons exhibited electrophysiological properties similar to those in HEK293 cells, and both ATP- and $\alpha$, $\beta$-meATP-induced currents in TG neurons were effectively blocked by TNP-ATP, suggesting that $P2X_3$ mediates the majority of ATP-induced currents in TG neurons. Eugenol inhibited ATP-induced currents in both capsaicin-sensitive and capsaicin-insensitive TG neurons with similar extent, and most ATP-responsive neurons were IB4-positive. Eugenol inhibited not only $Ca^{2+}$ transients evoked by $\alpha$, $\beta$-meATP, the selective $P2X_3$ agonist, in capsaicin-insensitive TG neurons, but also ATP-induced currents in $P2X_3$-expressing HEK293 cells without co-expression of transient receptor potential vanilloid 1 (TRPV1). We suggest, therefore, that eugenol inhibits $P2X_3$ currents in a TRPV1-independent manner, which contributes to its analgesic effect.