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Kyongmin Kim,Eunkyeom Kim,Youngill Kim,Jung Hyun Sok,Kyoungwan Park 한국물리학회 2016 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.69 No.12
Bipolar resistive switching in ZnO/SiOx bi-layer and ZnO/SiOx/ZnO tri-layer structures was investigated for nonvolatile memory applications. ZnO thin films were grown using the radiofrequency magnetron sputtering technique at room temperature. SiOx films were grown using plasma-enhanced chemical-vapor deposition at 200 C. Multiple high-resistance states were observed during the set process. The high/low resistance state ratio was 10 during 100 on/off cycles. The tri-layer memory device exhibited better endurance properties than the bi-layer device. Because an asymmetric conducting filament has a weak point for charge conduction at the oxide interfaces, we attributed the good endurance property to the reproducible formation/rupture of “micro”-conducting filaments. Moreover, the dynamics of the oxygen ions in the SiOx layer plays an important role in resistive switching.
NLRP3 Inflammasome Activation in THP-1 Target Cells Triggered by Pathogenic <i>Naegleria fowleri</i>
Kim, Jong-Hyun,Sohn, Hae-Jin,Yoo, Jong-Kyun,Kang, Heekyoung,Seong, Gi-Sang,Chwae, Yong-Joon,Kim, Kyongmin,Park, Sun,Shin, Ho-Joon American Society for Microbiology 2016 Infection and immunity Vol.84 No.9
<P>Naegleria fowleri, known as the brain-eating amoeba, causes acute primary amoebic meningoencephalitis. During swimming and other recreational water activities, N. fowleri trophozoites penetrate the nasal mucosa and invade the olfactory bulbs, resulting in intense inflammatory reactions in the forebrain tissue. To investigate what kinds of inflammasome molecules are expressed in target cells due to N. fowleri infection, human macrophage cells (THP-1 cells) were cocultured with N. fowleri trophozoites in a noncontact system, and consequently, interleukin-1 beta (IL-1 beta) production was estimated. Caspase-1 activation and IL-1 beta production from THP-1 cells by Western blotting and the culture supernatant by enzyme-linked immunosorbent assay analysis were observed at 3 h after cocultivation. In addition, the increased expression of ASC and NLRP3, which make up an inflammasome complex, was also observed at 3 h after cocultivation. To confirm the caspase-1 activation and IL-1 beta production via the NLRP3 inflammasome in THP-1 cells triggered by N. fowleri trophozoites, THP-1 cells were pretreated with several inhibitors. The inhibition assay showed that CA-074 (a cathepsin B inhibitor), glybenclamide (an NLRP3 molecule inhibitor), and N-benzyloxycarbony-Val-Ala-Asp(O-methyl)-fluoromethylketone (Z-VAD-FMK; a caspase-1 inhibitor) reduced the levels of caspase-1 activation and IL-1 beta production from THP-1 cells. This study suggests that N. fowleri infection induces the NLRP3 inflammasome, which activates caspase-1 and subsequently produces IL-1 beta, thus resulting in inflammation.</P>
The immune response induced by DNA vaccine expressing nfa1 gene against Naegleria fowleri
Kim, Jong-Hyun,Lee, Sang-Hee,Sohn, Hae-Jin,Lee, Jinyoung,Chwae, Yong-Joon,Park, Sun,Kim, Kyongmin,Shin, Ho-Joon Springer-Verlag 2012 Parasitology research Vol.111 No.6
<P>The pathogenic free-living amoeba, Naegleria fowleri, causes fatal primary amoebic meningoencephalitis in experimental animals and in humans. The nfa1 gene that was cloned from N. fowleri is located on pseudopodia, especially amoebic food cups and plays an important role in the pathogenesis of N. fowleri. In this study, we constructed and characterized retroviral vector and lentiviral vector systems for nfa1 DNA vaccination in mice. We constructed the retroviral vector (pQCXIN) and the lentiviral vector (pCDH) cloned with the egfp-nfa1 gene. The expression of nfa1 gene in Chinese hamster ovary cell and human primary nasal epithelial cell transfected with the pQCXIN/egfp-nfa1 vector or pCDH/egfp-nfa1 vector was observed by fluorescent microscopy and Western blotting analysis. Our viral vector systems effectively delivered the nfa1 gene to the target cells and expressed the Nfa1 protein within the target cells. To evaluate immune responses of nfa1-vaccinated mice, BALB/c mice were intranasally vaccinated with viral particles of each retro- or lentiviral vector expressing nfa1 gene. DNA vaccination using viral vectors expressing nfa1 significantly stimulated the production of Nfa1-specific IgG subclass, as well as IgG levels. In particular, both levels of IgG2a (Th1) and IgG1 (Th2) were significantly increased in mice vaccinated with viral vectors. These results show the nfa1-vaccination induce efficiently Th1 type, as well as Th2 type immune responses. This is the first report to construct viral vector systems and to evaluate immune responses as DNA vaccination in N. fowleri infection. Furthermore, these results suggest that nfal vaccination may be an effective method for treatment of N. fowleri infection.</P>
T Cell Immunoglobulin Mucin Domain (TIM)-3 Promoter Activity in a Human Mast Cell Line
Kim, Jung Sik,Shin, Dong-Chul,Woo, Min-Yeong,Kwon, Myung-Hee,Kim, Kyongmin,Park, Sun The Korean Association of Immunobiologists 2012 Immune Network Vol.12 No.5
T cell immunoglobulin mucin domain (TIM)-3 is an immunomodulatory molecule and upregulated in T cells by several cytokines. TIM-3 also influences mast cell function but its transcriptional regulation in mast cells has not been clarified. Therefore, we examined the transcript level and the promoter activity of TIM-3 in mast cells. The TIM-3 transcript level was assessed by real-time RT-PCR and promoter activity by luciferase reporter assay. TIM-3 mRNA levels were increased in HMC-1, a human mast cell line by TGF-${\beta}1$ stimulation but not by stimulation with interferon (IFN)-${\alpha}$, IFN-${\lambda}$, TNF-${\alpha}$, or IL-10. TIM-3 promoter -349~+144 bp region relative to the transcription start site was crucial for the basal and TGF-${\beta}1$-induced TIM-3 promoter activities in HMC-1 cells. TIM-3 promoter activity was increased by over-expression of Smad2 and Smad4, downstream molecules of TGF-${\beta}1$ signaling. Our results localize TIM-3 promoter activity to the region spanning -349 to +144 bp in resting and TGF-${\beta}1$ stimulated mast cells.
RNA Granules and Stress Granules in Virus Systems
Kim, Kyongmin 대한미생물학회 2012 Journal of Bacteriology and Virology Vol.42 No.3
Viruses initiate a number of cellular stress responses and modulate gene regulation and compartmentalization of RNA upon infection to be successful parasites. Virus infections may induce or impair stress granule (SG) formation to maximize replication efficiency. SGs and processing bodies (PBs) are the RNA granules, which contain translationally inactive pool of transcripts as the mRNA silencing foci. PBs and SGs, the highly conserved macromolecular aggregates, can release mRNAs to allow their translations. Unlike constitutively existing PBs that can respond to stimuli and affect mRNA translation and decay, SGs are specifically induced upon cellular stress and can triggers a global translational silencing by several pathways, including phosphorylation of the key translation initiation factor eIF2alpha, tRNA cleavage, and sequestration of cellular components and so on. The dynamics of PBs and SGs are regulated by several signaling pathways, including histone deacetylase 6, and depend on microfilaments and microtubules, and the cognate molecular motors myosin, dynein, and kinesin. SGs share features with aggresomes and related aggregates of unfolded proteins and may play a role in the pathology. The recent advances in understanding the relationship between viruses and mRNA stress granules are summarized.
Kim, Hye-Young,Eo, Eun-Young,Park, Hyun,Kim, Youn-Chul,Park, Sun,Shin, Ho-Joon,Kim, Kyongmin International Medical Press 2010 ANTIVIRAL THERAPY Vol.15 No.5
<P>BACKGROUND: Cimicifuga rhizome, Meliae cortex, Coptidis rhizome and Phellodendron cortex have been previously shown to exhibit anti-coronavirus activity. Here, an additional 19 traditional medicinal herbal extracts were evaluated for antiviral activities in vitro. METHODS: A plaque assay was used to evaluate the effects of 19 extracts, and the concentration of extract required to inhibit 50% of the replication (EC(50)) of mouse hepatitis virus (MHV) A59 strain (MHV-A59) was determined. The 50% cytotoxic concentration (CC(50)) of each extract was also determined. Northern and western blot analyses were conducted to evaluate antiviral activity on viral entry, viral RNA and protein expression, and release in MHV-infected DBT cells. RESULTS: Sophorae radix, Acanthopanacis cortex and Torilis fructus reduced intracellular viral RNA levels with comparable reductions in viral proteins and MHV-A59 production. The extracts also reduced the replication of the John Howard Mueller strain of MHV, porcine epidemic diarrhoea virus and vesicular stomatitis virus in vitro. Sanguisorbae radix reduced coronavirus production, partly as a result of decreased protein synthesis, but without a significant reduction in intracellular viral RNA levels. The EC(50) values of the four extracts ranged from 0.8 to 3.7 mug/ml, whereas the CC(50) values ranged from 156.5 to 556.8 mug/ml. Acanthopanacis cortex and Torilis fructus might exert their antiviral activities in MHV-A59-infected cells by inducing cyclooxygenase-2 expression via the activation of extracellular signal-related kinase (ERK) and p38 or ERK alone, respectively. CONCLUSIONS: Sophorae radix, Acanthopanacis cortex, Sanguisorbae radix and Torilis fructus might be considered as promising novel anti-coronavirus drug candidates.</P>