• Genomics & Informatics
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• v.2 no.2
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• pp.67-74
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• 2004

Cells consistently face stressful conditions, which cause them to modulate a variety of intracellular processes and adapt to these environmental changes via regulation of gene expression. Hyperosmotic and oxidative stresses are significant stressors that induce cellular damage, and finally cell death. In this study, oligonucleotide microarrays were employed to investigate mRNA level changes in cells exposed to hyperosmotic or oxidative conditions. In addition, since heat shock protein 70 (HSP70) is one of the most inducible stress proteins and plays pivotal role to protect cells against stressful condition, we performed microarray analysis in HSP70-overexpressing cells to identify the genes expressed in a HSP70-dependent manner. Under hyperosmotic or oxidative stress conditions, a variety of genes showed altered expression. Down­regulation of protein phosphatase1 beta (PP1 beta) and sphingosine-1-phosphate phosphatase 1 (SPPase1) was detected in both stress conditions. Microarray analysis of HSP70-overexpressing cells demonstrated that diverse mRNA species depend on the level of cellular HSP70. Genes encoding Iysyl oxidase, thrombospondin 1, and procollagen displayed altered expression in all tested conditions. The results of this study will be useful to construct networks of stress response genes.

• BMB Reports
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• v.37 no.4
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• pp.402-407
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• 2004

A human gene T-complex protein 10 like (TCP10L) was cloned in our lab. A previous study showed that it expressed specifically in the liver and testis. A transcription experiment revealed that TCP10L was a transcription factor with transcription inhibition activity. In this study, the human MAD4 was identified to interact with TCP10L by a yeast two-hybrid screen. This finding was confirmed by immunoprecipitation and subcellular localization experiments. As MAD4 is a member of the MAD family, which antagonizes the functions of MYC and promotes cell differentiation, the biological function of the interaction between TCP10L and MAD4 may be to maintain the differentiation state in liver cells. Also, we propose that the up-regulation of Myc is caused by the down-regulation of TCP10L in human hepatocarcinomas.

• BMB Reports
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• v.41 no.11
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• pp.765-770
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• 2008

Undesirable hyperpigmentation that can arise from increased melanocyte activity may be alleviated by targeting active melanocytes for apoptosis. The role of Stathmin 1 as an important regulator of microtubule dynamics is well documented. The current study examined the potential of Stathmin 1-targeting strategies in eliminating active melanocytes. A vector to overexpress Stathmin 1 and vectors to express three distinct small hairpin RNAs to knockdown Stathmin 1 expression in normal melanocytes were produced and in cell cultures acted accordingly. Both overexpression and knockdown of Stathmin 1 led to a marked increase in melanocyte apoptosis, as indicated by the accumulation of apoptotic cells and increased levels of cleaved caspase-3. Both up- and down-regulation of Stathmin 1 expression inhibited the activity of differentiated melanocytes, as indicated by decreases in both melanin production and tyrosinase activity. Taken together, these results indicate that hyperactive melanocytes can be inhibited by altering Stathmin 1 expression.

• Journal of Life Science
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• v.19 no.7
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• pp.866-870
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• 2009

Fascin, a cytoskeleton actin binding protein, functions in cell adhesion and cell migration. Fascin is also known as a candidate biomarker for various cancers, however, regulatory mechanisms of fascin expression remains little understood. In this study, we found an abnormal bristle phenotype, which is similar to that of the Drosophila fascin mutant, in Drafmutant flies. Hence, we investigated whether fascin expression is regulated by Raf signaling. RT-PCR and Western blot analysis showed that Drosophila fascin expression was down-regulated in Draf mutant flies and the level was increased in larvae expressing the oncogenic form of Draf (Draf$^{got}$) under the GAL4-UAS system. Immunostaining analysis showed increased fascin in the hemocytes over-expressing Draf$^{got}$. Our results indicate that fascin expression is regulated by Raf signaling and suggest that Raf signaling may play an important role in the actin cytoskeleton-associated developmental process and tumor progression via regulation of fascin gene.

• Journal of Pharmacopuncture
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• v.12 no.1
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• pp.67-76
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• 2009

Objective : Following central nervous system(CNS) injury, inhibitory influences at the site of axonal damage occur. Glial cells become reactive and form a glial scar, gliosis. Also myelin debris such as MAG inhibits axonal regeneration. Astrocyte-rich gliosis relates with up-regulation of GFAP and CD81, and eventually becomes physical and mechanical barrier to axonal regeneration. MAG is one of several endogenous axon regeneration inhibitors that limit recovery from CNS injury and disease. It was reported that molecules that block such inhibitors enhanced axon regeneration and functional recovery. Recently it was reported that treatment with anti-CD81 antibodies enhanced functional recovery in the rat with spinal cord injury. So in this current study, the author investigated the effect of the water extract of Uncariae Ramulus et Uncus on the regulation of CD81, GFAP and MAG that increase when gliosis occurs. Methods : MTT assay was performed to examine cell viability, and cell-based ELISA, western blot and PCR were used to detect the expression of CD81, GFAP and MAG. Then also immunohistochemistry was performed to confirm in vivo. Results : Water extract of Uncariae Ramulus et Uncus showed relatively high cell viability at the concentration of 0.05%, 0.1% and 0.5%. The expression of CD81, GFAP and MAG in astrocytes was decreased after the administration of Uncariae Ramulus et Uncus water extract. These results was confirmed in the brain sections following cortical stab injury by immunohistochemistry. Conclusion : The authors observed that Uncariae Ramulus et Uncus significantly down-regulates the expression of CD81, GFAP and MAG. These results suggest that Uncariae Ramulus et Uncus can be a candidate to regenerate CNS injury.

• Journal of Embryo Transfer
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• v.28 no.4
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• pp.361-371
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• 2013

The present study assessed the effect of FSH and LH on oocyte meiotic, cytoplasmic maturation and on the expression level and polyadenylation status of several maternal genes. Cumulus-oocyte complexes were cultured in the presence of FSH, LH, or the combination of FSH and LH. Significant cumulus expansion and nuclear maturation was observed upon exposure to FSH alone and to the combination of FSH and LH. The combination of FSH and LH during entire IVM increased the mRNA level of four maternal genes, C-mos, Cyclin B1, Gdf9 and Bmp15, at 28 h. Supplemented with FSH or LH significantly enhanced the polyadenylation of Gdf9 and Bmp15; and altered the expression level of Gdf9 and Bmp15. Following parthenogenesis, the exposure of oocytes to combination of FSH and LH during IVM significantly increased cleavage rate, blastocyst formation rate and total cell number, and decreased apoptosis. In addition, FSH and LH down-regulated the autophagy gene Atg6 and upregulated the apoptosis gene Bcl-xL at the mRNA level in blastocysts. These data suggest that the FSH and LH enhance meiotic and cytoplasmic maturation, possibly through the regulation of maternal gene expression and polyadenylation. Overall, we show here that FSH and LH inhibit apoptosis and autophagy and improve parthenogenetic embryo competence and development.

• The Korean Journal of Physiology and Pharmacology
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• v.22 no.3
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• pp.277-289
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• 2018

The exponential increase in the use of mobile communication has triggered public concerns about the potential adverse effects of radiofrequency electromagnetic fields (RF-EMF) emitted by mobile phones on the central nervous system (CNS). In this study, we explored the relationship between calcium channels and apoptosis or autophagy in the hippocampus of C57BL/6 mice after RF-EMF exposure with a specific absorption rate (SAR) of 4.0 W/kg for 4 weeks. Firstly, the expression level of voltage-gated calcium channels (VGCCs), a key regulator of the entry of calcium ions into the cell, was confirmed by immunoblots. We investigated and confirmed that pan-calcium channel expression in hippocampal neurons were significantly decreased after exposure to RF-EMF. With the observed accumulation of autolysosomes in hippocampal neurons via TEM, the expressions of autophagy-related genes and proteins (e.g., LC3B-II) had significantly increased. However, down-regulation of the apoptotic pathway may contribute to the decrease in calcium channel expression, and thus lower levels of calcium in hippocampal neurons. These results suggested that exposure of RF-EMF could alter intracellular calcium homeostasis by decreasing calcium channel expression in the hippocampus; presumably by activating the autophagy pathway, while inhibiting apoptotic regulation as an adaptation process for 835 MHz RF-EMF exposure.

• Journal of Power Electronics
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• v.15 no.2
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• pp.555-566
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• 2015

A TRIAC dimming LED driver that can control the brightness of LED arrays for a wide range of source voltage variations is proposed in this paper. Unlike conventional PWM LED drivers, the proposed LED driver adopts a TRIAC switch, which inherently guarantees zero current switching and has been proven to be quite reliable over its long lifetime. Unlike previous TRIAC type LED drivers, the proposed LED driver is composed of an LC input filter and a variable switched capacitance, which is modulated by the TRIAC turn-on timing. Thus, the LED power regulation and dimming control, which are done by a volume resistor in the same way as the conventional TRIAC dimmers, can be simultaneously performed by the TRIAC control circuit. Because the proposed LED driver has high efficiency and a long lifetime with a high power factor (PF) and low total harmonic distortion (THD) characteristics, it is quite adequate for industrial lighting applications such as streets, factories, parking garages, and emergency stairs. A simple step-down capacitive power supply circuit composed of passive components only is also proposed, which is quite useful for providing DC power from an AC source without a bulky and heavy transformer. A prototype 60 W LED driver was implemented by the proposed design procedure and verified by simulation and experimental results, where the efficiency, PF, and THD are 92%, 0.94, and 6.3%, respectively. The LED power variation is well mitigated to below ${\pm}2%$ for 190 V < $V_s$ < 250 V by using the proposed simple control circuit.

• The Journal of Internal Korean Medicine
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• v.30 no.1
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• pp.51-63
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• 2009

Background and Objective : The prospects for developing an anti-apoptotic natural component or a compound that exerts a neuroprotective effect with few or no side effects for the treatment of neurodegenerative disease appear favorable. In the present study, we evaluated the effects of the methanol extract of Phellodendri Cortex (PC extract) on 1-methyl-4-phenyl pyridinium($MPP^+$)-induced apoptosis in PC-12 cells. Materials and Methods : We used the methanol extract of Phellodendri Cortex (PC extract). PC-12 cells were cultured by RPMZ-1640. We found the PC extract's gene expression (Bax, Bcl-2) by using RT-PCR. We examined the PC extract's protein expression (Bcl-2, Bax, cytochrome c, poly (ADP-ribose) polymerase (PARP), caspase-3) by SDS-PAGE and Western blot. Results : Apoptosis in $MPP^+$-induced PC-12 cells was accompanied by an increased Bax/Bcl-2 ratio, release of cytochrome c to the cytosol and the activation of caspase-3. PC extract inhibited the down-regulation of Bcl-2 and the up-regulation of Bax, as well as the release of mitochondrial cytochrome c into the cytosol. In addition, PC extract attenuated caspase-3 activation and cleavage of poly (ADP-ribose) polymerase (PARP). Conclusion : These results suggest that the neuroprotective potentials of PC extract against $MPP^+$-induced apoptosis can be. at least partially, ascribed to its anti-apoptotic effects in PC-12 cells.

• Journal of Physiology & Pathology in Korean Medicine
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• v.20 no.6
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• pp.1548-1555
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• 2006

Bujeonghangam-tang(BHT) has been used as an anticancer agent in oriental medicine, but the mechanism by which it induces cell death in cancer cells is still unclear. To investigate cell death mechanism by BHT in cancer cells, the activities of apoptosis signaling pathway were tested in human neuroblastoma cell line LAN5. Viability of LAN5 cells was markedly decreased by treatment of the water extract of BHT in a dose-dependent manner. BHT induced cell death was confirmed as apoptosis characterized by chromatin condensation. We tested whether the water extract of BHT affects the anti-apoptotic protein such as Bcl-2 and Bcl-XL, and the pro-apoptotic protein such as Bax. Both Bcl-2 and Bcl-XL were gradually decreased but Bas was increased in a time-dependent manner after the addition of the water extract of BHT. Cleavage of Bid by activation of caspase-8 protease was also observed in LAN-5 cells by the treatment of the water extract of BHT. Taken together, these results suggest that the water extract of BHT exerts anti-cancer effects on human neuroblastoma LAN-5 cells by inducing the apoptotic death via down-regulation of anti-apoptotic proteins such as Bcl-2 and Bcl-XL, up-regulation of pro-apoptotic protein such as Bax, and activation of intrinsic caspase cascades.