• The Korean Journal of Physiology and Pharmacology
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• v.12 no.6
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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.

• Environmental Mutagens and Carcinogens
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• v.25 no.1
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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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• v.42 no.5
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• pp.418-425
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• 2019

Multicistronic elements, such as the internal ribosome entry site (IRES) and 2A-like cleavage sequence, serve crucial roles in the eukaryotic ectopic expression of exogenous genes. For utilization of multicistronic elements, the cleavage efficiency and order of elements in multicistronic vectors have been investigated; however, the dynamics of multicistronic element-mediated expression remains unclear. Here, we investigated the dynamics of encephalomyocarditis virus (EMCV) IRES- and porcine teschovirus-1 2A (p2A)-mediated expression. By utilizing real-time fluorescent imaging at a minute-level resolution, we monitored the expression of fluorescent reporters bridged by either EMCV IRES or p2A in two independent cultured cell lines, HEK293 and Neuro2a. We observed significant correlations for the two fluorescent reporters in both multicistronic elements, with a higher correlation coefficient for p2A in HEK293 but similar coefficients for IRES-mediated expression and p2A-mediated expression in Neuro2a. We further analyzed the causal relationship of multicistronic elements by convergent cross mapping (CCM). CCM revealed that in all four conditions examined, the expression of the preceding gene causally affected the dynamics of the subsequent gene. As with the cross correlation, the predictive skill of p2A was higher than that of IRES in HEK293, while the predictive skills of the two multicistronic elements were indistinguishable in Neuro2a. To summarize, we report a significant temporal correlation in both EMCV IRES- and p2A-mediated expression based on the simple bicistronic vector and real-time fluorescent monitoring. The current system also provides a valuable platform to examine the dynamic aspects of expression mediated by diverse multicistronic elements under various physiological conditions.

• 한국생물공학회:학술대회논문집
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• 2003.04a
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• pp.132-132
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• 2003

• Proceedings of the PSK Conference
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• 2002.04a
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• pp.123.1-123.1
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• 2002

• Carbon letters
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• v.17 no.1
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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.

• Molecules and Cells
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• v.25 no.1
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• pp.43-49
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• 2008

Cancer Osaka thyroid, also known as Tpl-2 (Cot) is a member of the MAP3K kinase family and plays a key role in the regulation of the immune response to pro-inflammatory stimuli such as lipopolysaccharide (LPS) and tumour necrosis $factor-{\alpha}$ ($TNF-{\alpha}$). A series of Cot constructs with an N-terminal 6xHis tag were transiently expressed in HEK293 cells: $Cot_{130-399}$ (kinase domain), $Cot_{1-388}$ (N-terminal and kinase do-mains), $Cot_{1-413}$, $Cot_{1-438}$ (containing a putative PEST sequence), $Cot_{1-457}$ (containing both PEST and degron sequences) and $Cot_{1-467}$ (full-length protein). These Cot proteins were pulled down using an anti-6xHis antibody and separated by 2D electrophoresis. The gels were silver-stained and 21 proteins were detected that did not appear, or had substantially reduced intensity, in the control sample. Three of these were identified by MS and MS/MS analysis as Hsp90, Hsp70 and Grp78. Hsp90 appeared to bind to the kinase domain of Cot and this interaction was further investigated using co-immuno-precipitation with both overexpressed Cot in HEK293 cells and endogenous Cot in Hela cells.

• Biomolecules & Therapeutics
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• v.25 no.5
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• pp.497-503
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• 2017

Recent reports claimed that glucosylsphingosine (GS) is highly accumulated and specifically evoking itch-scratch responses in the skins of atopic dermatitis (AD) patients. However, it was unclear how GS can trigger itch-scratch responses, since there were no known molecular singling pathways revealed yet. In the present study, it was verified for the first time that GS can activate mouse serotonin receptor 2a (mHtr2a) and 2b (mHtr2b), but not 2c (mHtr2c) that are expressed in HEK293T cells. Specifically, effects of GS on all mouse serotonin receptor 2 subfamily were evaluated by calcium imaging techniques. The GS-induced intracellular calcium increase was dose-dependent, and antagonists such as ketanserin (Htr2a antagonist) and RS-127445 (Htr2b antagonist) significantly blocked the GS-induced responses. Moreover, the proposed GS-induced responses appear to be mediated by phospholipase C (PLC), since pretreatment of a PLC inhibitor U-73122 abolished the GS-induced responses. Additionally, the GS-induced calcium influx is probably mediated by endogenous TRPC ion channels in HEK293T cells, since pretreatment of SKF-96365, an inhibitor for TRPC, significantly suppressed GS-induced response. In conclusion, the present study revealed for the first time that GS can stimulate mHtr2a and mHtr2b to induce calcium influx, by utilizing PLC-dependent pathway afterwards. Considering that GS is regarded as a pruritogen in AD, the present study implicates a novel GS-induced itch signaling pathway.

• Animal cells and systems
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• v.16 no.5
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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.

• Korean Journal of Plant Resources
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• v.30 no.6
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• pp.679-685
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• 2017

Stachys affinis tubers are known for its high content of stachyose and eaten as an edible vegetable. In this work, we assessed on the anti-inflammatory and anti-proliferation activity of a various type of extracts derived from S. affinis tubers. The n-hexane and dichloromethane fractions were showed the high cytotoxicity on the cell lines including RAW264.7 macrophages, HEK293 human kidney cell, A549 human lung cancer cell, KB human oral cancer cell, and a PC-3 human prostate cancer cell. N-butanol and water fractions were not exhibited cytotoxicity on the tested cancer cells, limited in anti-inflammatory and anti-cancer activities. Nevertheless, the ethyl acetate fraction showed little harm to RAW264.7 cells but inhibited the production of nitric oxide (NO) and prostaglandin E2 (PGE2) significantly. In addition, it arrests the cell growth in A549, KB, and PC-3 cell while little cytotoxicity on HEK293 cells. Consequently, these results supported that the ethyl acetate fraction of S. affinis tubers could be a potential anti-inflammatory and anti-cancer ingredient.