• Animal cells and systems
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• v.14 no.3
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• pp.147-154
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• 2010

It is well-established that phosphoinositide 3-kinase (PI3-kinase) regulates myogenesis by inducing transcription of myogenin, a key muscle regulatory factor, at the initiation of myoblast differentiation. In this study, we investigated the role of PI3-kinase in cells that have committed to differentiation. PI3-kinase activity increases during myogenesis, and this increase is sustained during the myogenic process; however, its function after the induction of differentiation has not been investigated. We show that LY294002, a PI3-kinase inhibitor, blocked myoblast fusion even after myogenin expression initially increased. In contrast to the inhibitory effects of LY294002 on myogenin mRNA levels during the initiation of differentiation, LY294002 blocked the accumulation of myogenin protein without affecting its mRNA level after differentiation was induced. Treatment with cycloheximide, a translation inhibitor, or actinomycin D, a transcription inhibitor, indicated that the stability of myogenin protein is lower than that of its mRNA. LY294002 inhibited the activities of several important translation factors, including eukaryotic elongation factor-2(eEF2), by altering their phosphorylation status. In addition, LY294002 blocked the incorporation of [$^{35}S$]methionine into newly synthesized proteins. Since myogenin has a relatively short half-life, LY294002-mediated inhibition of post-transcriptional processes resulted in a rapid depletion of myogenin protein. In summary, these results suggest that PI3-kinase plays an important role in regulating the expression of myogenin through post-transcriptional mechanisms after differentiation has been induced.

• The Korean Journal of Physiology and Pharmacology
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• v.23 no.2
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• pp.121-130
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• 2019

Glutamate toxicity-mediated mitochondrial dysfunction and neuronal cell death are involved in the pathogenesis of several neurodegenerative diseases as well as acute brain ischemia/stroke. In this study, we investigated the neuroprotective mechanism of dieckol (DEK), one of the phlorotannins isolated from the marine brown alga Ecklonia cava, against glutamate toxicity. Primary cortical neurons ($100{\mu}M$, 24 h) and HT22 neurons (5 mM, 12 h) were stimulated with glutamate to induce glutamate toxic condition. The results demonstrated that DEK treatment significantly increased cell viability in a dose-dependent manner ($1-50{\mu}M$) and recovered morphological deterioration in glutamate-stimulated neurons. In addition, DEK strongly attenuated intracellular reactive oxygen species (ROS) levels, mitochondrial overload of $Ca^{2+}$ and ROS, mitochondrial membrane potential (${\Delta}{\Psi}_m$) disruption, adenine triphosphate depletion. DEK showed free radical scavenging activity in the cell-free system. Furthermore, DEK enhanced protein expression of heme oxygenase-1 (HO-1), an important anti-oxidant enzyme, via the nuclear translocation of nuclear factor-like 2 (Nrf2). Taken together, we conclude that DEK exerts neuroprotective activities against glutamate toxicity through its direct free radical scavenging property and the Nrf-2/HO-1 pathway activation.

• Molecules and Cells
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• v.44 no.2
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• pp.101-115
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• 2021

The INO80 chromatin remodeling complex has roles in many essential cellular processes, including DNA replication. However, the mechanisms that regulate INO80 in these processes remain largely unknown. We previously reported that the stability of Ino80, the catalytic ATPase subunit of INO80, is regulated by the ubiquitin proteasome system and that BRCA1-associated protein-1 (BAP1), a nuclear deubiquitinase with tumor suppressor activity, stabilizes Ino80 via deubiquitination and promotes replication fork progression. However, the E3 ubiquitin ligase that targets Ino80 for proteasomal degradation was unknown. Here, we identified the C-terminus of Hsp70-interacting protein (CHIP), the E3 ubiquitin ligase that functions in cooperation with Hsp70, as an Ino80-interacting protein. CHIP polyubiquitinates Ino80 in a manner dependent on Hsp70. Contrary to our expectation that CHIP degrades Ino80, CHIP instead stabilizes Ino80 by extending its half-life. The data suggest that CHIP stabilizes Ino80 by inhibiting degradative ubiquitination. We also show that CHIP works together with BAP1 to enhance the stabilization of Ino80, leading to its chromatin binding. Interestingly, both depletion and overexpression of CHIP compromise replication fork progression with little effect on fork stalling, as similarly observed for BAP1 and Ino80, indicating that an optimal cellular level of Ino80 is important for replication fork speed but not for replication stress suppression. This work therefore idenitifes CHIP as an E3 ubiquitin ligase that stabilizes Ino80 via nondegradative ubiquitination and suggests that CHIP and BAP1 act in concert to regulate Ino80 ubiquitination to fine-tune its stability for efficient DNA replication.

• BMB Reports
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• v.54 no.6
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• pp.311-316
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• 2021

Ethanol often causes critical health problems by altering the neuronal activities of the central and peripheral nerve systems. One of the cellular targets of ethanol is the plasma membrane proteins including ion channels and receptors. Recently, we reported that ethanol elevates membrane excitability in sympathetic neurons by inhibiting Kv7.2/7.3 channels in a cell type-specific manner. Even though our studies revealed that the inhibitory effects of ethanol on the Kv7.2/7.3 channel was diminished by the increase of plasma membrane phosphatidylinositol 4,5-bisphosphate (PI(4,5)P₂), the molecular mechanism of ethanol on Kv7.2/7.3 channel inhibition remains unclear. By investigating the kinetics of Kv7.2/7.3 current in high K⁺ solution, we found that ethanol inhibited Kv7.2/7.3 channels through a mechanism distinct from that of tetraethylammonium (TEA) which enters into the pore and blocks the gate of the channels. Using a non-stationary noise analysis (NSNA), we demonstrated that the inhibitory effect of ethanol is the result of reduction of open probability (P_O) of the Kv7.2/7.3 channel, but not of a single channel current (i) or channel number (N). Finally, ethanol selectively facilitated the kinetics of Kv7.2 current suppression by voltage-sensing phosphatase (VSP)-induced PI(4,5)P₂ depletion, while it slowed down Kv7.2 current recovery from the VSP-induced inhibition. Together our results suggest that ethanol regulates neuronal activity through the reduction of open probability and PI(4,5)P₂ sensitivity of Kv7.2/7.3 channels.

• Journal of Microbiology and Biotechnology
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• v.31 no.2
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• pp.304-316
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• 2021

Vaccination is the most effective way to prevent influenza virus infections. However, conventional vaccines based on hemagglutinin (HA) have to be annually updated because the HA of influenza viruses constantly mutates. In this study, we produced a 3M2e-3HA2-NP chimeric protein as a vaccine antigen candidate using an Escherichia coli expression system. The vaccination of chimeric protein (15 ㎍) conferred complete protection against A/Puerto Rico/8/1934 (H1N1; PR8) in mice. It strongly induced influenza virus-specific antibody responses, cytotoxic T lymphocyte activity, and antibody-dependent cellular cytotoxicity. To spare the dose and enhance the cross-reactivity of the chimeric, we used a complex of poly-γ-glutamic acid and alum (PGA/alum) as an adjuvant. PGA/alum-adjuvanted, low-dose chimeric protein (1 or 5 ㎍) exhibited higher cross-protective effects against influenza A viruses (PR8, CA04, and H3N2) compared with those of chimeric alone or alum-adjuvanted proteins in vaccinated mice. Moreover, the depletion of CD4+ T, CD8+ T, and NK cells reduced the survival rate and efficacy of the PGA/alum-adjuvanted chimeric protein. Collectively, the vaccination of PGA/alum-adjuvanted chimeric protein induced strong protection efficacy against homologous and heterologous influenza viruses in mice, which suggests that it may be a promising universal influenza vaccine candidate.

• Journal of IKEEE
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• v.25 no.1
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• pp.193-200
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• 2021

In order to prevent illegal fishing and reduce lost fishing gear, it is necessary to develop a constant and continuous fishing gear monitoring system in the marine environment. In this paper, we design a long-term operational, reliable system model with communication coverage of more than 25Km considering the reality of gradually expanding fishing activity due to the depletion of fishery resources and marine environments. The design results are implemented to verify the operability of the system by separating the communication success rate of SKT and private LoRa networks and verifying the control function of each control system through the collected location information, respectively.

• Molecules and Cells
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• v.45 no.6
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• pp.365-375
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• 2022

Long non-coding RNAs (lncRNAs) may be important regulators in the progression of ankylosing spondylitis (AS). The competing endogenous RNA (ceRNA) activity of lncRNAs plays crucial roles in osteogenesis. We identified the mechanism of the differentially expressed lncRNA MALAT1 in AS using bioinformatic analysis and its ceRNA mechanism. The interaction of MALAT1, microRNA-558, and GSDMD was identified using integrated bioinformatics analysis and validated. Loss- and gain-of-function assays evaluated their effects on the viability, apoptosis, pyroptosis and inflammation of chondrocytes in AS. We found elevated MALAT1 and GSDMD but reduced miR-558 in AS cartilage tissues and chondrocytes. MALAT1 contributed to the suppression of cell viability and facilitated apoptosis and pyroptosis in AS chondrocytes. GSDMD was a potential target gene of miR-558. Depletion of MALAT1 expression elevated miR-558 by inhibiting GSDMD to enhance cell viability and inhibit inflammation, apoptosis and pyroptosis of chondrocytes in AS. In summary, our key findings demonstrated that knockdown of MALAT1 served as a potential suppressor of AS by upregulating miR-558 via the downregulation of GSDMD expression.

• The Korea Journal of Herbology
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• v.38 no.1
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• pp.21-30
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• 2023

Objective : Gardeniae Fructus (GF) has bitter and cold nature. Thus, it has been traditionally prescribed in processed form roasted with ginger juice for patients with a weak stomach. This study investigated the effects of processed GF in tert-butyl hydroperoxide (tBHP)-treated gastric epithelial cells. Methods : Processed GF was made by applying 40% ginger juice or 10% ethanol for 24 h and then roasting at 150℃ for 5 minutes. Apoptosis was determined by terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay. Mitochondrial membrane potential (MMP) was monitored by flow cytometry using the membrane permeable fluorescent dye Rh123. Protein expression was measured by Western blot analysis. Results : Cell viability was reduced by tBHP and restored by ethanol extract of GF (GFE). In the TUNEL assay, it was found that cell death by tBHP was due to apoptosis, and GFE had an anti-apoptotic effect. Processed GF roasted with ginger juice showed the best anti-apoptotic effect. Processed GF also inhibited MMP loss and restored tBHP-induced changes in expression levels of apoptosis-related proteins. Increased ROS production and GSH depletion after tBHP treatment were significantly reduced by processed GF. In addition, tBHP-induced activation of mitogen-activated protein kinase (MAPK) was inhibited by processed GF. Conclusion : These results demonstrate that the processed GF is able to protect gastric epithelial cells from oxidative stress-induced cell death with antiapoptotic and antioxidant activity. In addition, it shows that the processing of GF, which have been traditionally used for gastrointestinal protection, partially have scientific validity.

• The Journal of the Convergence on Culture Technology
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• v.8 no.3
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• pp.99-104
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• 2022

This study was to analyze the effects of sudden rise in cortisol and human symptoms in the situation of rescue at river, The experimental results are as follows. The subjects were A, B, C, and the values of cortisol elevation before and after diving were 6.30ug/dl, 6.50ug/dl, and 6.57ug/dl, respectively. However, in the subject D, the elevation of cortisol before and after diving was significantly elevated to 11.00ug/dl. The reason for this is thought to be the depletion of physical strength through weighty due to the inferiority of the underwater view and tense during the sudden rise. The subjects E showed significantly lower cortisol elevation before and after diving, as 4.28ug/dl, because the age of E was the youngest of the subjects and the anxiety was low due to abundant experience of deep sea diving. Fatigue is 7 to 8, anxiety is 7 to 9, Both showed high values. Psychological strain increased fatigue in underwater search, and poor visual field seemed to increase anxiety. The research results will be provided as empirical data on the safe underwater search activities of rescuers.

• The Journal of Korean Obstetrics and Gynecology
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• v.22 no.1
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• pp.31-40
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• 2009

Purpose: This study was carried out to investigate the anti-tumor metastasis effect and activation of innate immunity by extracts of Mori radicis cortex. Methods: Anti-tumor metastatic experiment was conducted in vitro and in vivo by using colon 26-M3.1 carcinoma cell, L5178Y-R lymphoma cell and HeLa cell. To observe the activation of innate immunity by extracts of Mori radicis cortex, we estimated IL-6, IL-10, IL-12, TNF-${\alpha}$ from peritoneal macrophages. And we evaluated the activation of NK cell by using anti-asialo-GM1 serum. Results: We found that the administration of Mori radicis cortex extracts significantly inhibited tumor metastasis. In an in vitro cytotoxicity analysis, Mori radicis cortex affected tumor cell growth above specific concentration. Mori radicis cortex also stimulated peritoneal macrophage, which was followed by the production of various cytokines such as IL-6, IL-10, IL-12, TNF-${\alpha}$. The depletion of NK cells by anti-asialo GM1 serum partly abolished the inhibitory effect of Mori radicis cortex on tumor metastasis. Conclusion: Mori radicis cortex appears to have considerable activity on the anti-metastasis by activation of innate immunity.