• Journal of Plant Biotechnology
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• v.32 no.4
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• pp.269-273
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• 2005

Toll-like receptors (TLR) are important components of innate immunity in the defense against pathogens. TLRs recognize pathogen-associated common molecular patterns. TLRs are similar to the receptors involved in defense responses in plants. TLR protein is a type 1 membrane protein, consisting of an extracellular domain containing leucine-rich repeats and a cytoplasmic domain. The cytoplasmic domain delivers ligand recognition signals that result in production of anti-microbial agents. The cytoplasmic domain (amino acid 858-1032) of toll-like receptor 9 has been expressed using methylotrophic yeast Pichia pastoris. The protein expression was confirmed by Western-blot, N-terminal sequencing and MALDl-TOF mass spectrometry. The proteins have been purified by nickel affinity, cation exchange and gel-filtration chromatography.

• Journal of Microbiology and Biotechnology
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• v.16 no.3
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• pp.391-398
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• 2006

$NF-{\kappa}B$ is a transcription factor involved in the innate immunity against bacterial infection and inflammation. It is also known to render cells resistant to the apoptosis caused by some anticancer drugs. Such a chemoresistance of cancer cells may be related to the activation of $NF-{\kappa}B$ transcription factor; however, the mechanism of activation is not well understood. Here, we demonstrate that a chemotherapeutic agent, etoposide, independently stimulates the $I{\kappa}B{\alpha}$ degradation pathway and PI3-kinase/Akt signaling pathway: The classical $I{\kappa}B{\alpha}$ degradation pathway leads to the nuclear translocation and DNA binding of p65 subunit through $IKK{\beta}$ kinase, whereas the PI3-kinase/Akt pathway plays a distinct role in activating this transcription factor. The PI3-kinase/Akt pathway acts on the p50 subunit of the $NF-{\kappa}B$ transcription factor and enhances the DNA binding affinity of the p50 protein. It may also explain the role of the PI3-kinase/Akt pathway in the anti-apoptotic function of $NF-{\kappa}B$ during chemoresistance of cancer cells.

• Journal of fish pathology
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• v.25 no.1
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• pp.11-20
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• 2012

C-type lectins are crucial for pathogen recognition, innate immunity, and cell-cell interactions. In this study, a C-type lectin gene was cloned from the rock bream. The full-length RbCTL cDNA was 729 bp with a 429 bp ORF encoding a 164-residue protein. The deduced amino acid sequence of RbCTL had all of the conserved features crucial for its fundamental structure, including the four cysteine residues involved in sulfide bridge formation and potential $Ca^2+$/carbohydrate-binding sites. RbCTL contains a signal peptide one single carbohydrate recognition domain. It showed 29.4% similarity to the C-type lectin of rainbow trout. RbCTL mRNA was predominately expressed in gill and head-kidney tissue and expressed less in peripheral blood leukocytes, trunk-kidney, spleen, liver, intestine and muscle. Expression of RbCTL was differentially upregulated in rock bream stimulated with LPS, Con A/PMA and poly I:C.

• BMB Reports
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• v.46 no.9
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• pp.448-453
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• 2013

CpG-DNA has various immunomodulatory effects in dendritic cells, B cells, and macrophages. While induction of cytokines by CpG-DNA has been well documented in macrophages, the expression of costimulatory molecules in CpG-DNA treated macrophages has not yet been defined. Therefore, we investigated the effects of CpG-DNA on the expression of costimulatory molecules in RAW 264.7 cells. The surface expression of CD80 was slightly increased and CD83 expression was significantly increased in response to CpG-DNA. However, the expression of CD86 and MHC class II was not changed. As expression of CD83 mRNA was also increased by CpG-DNA, CD83 expression is regulated at a transcriptional level. To understand the contribution of signaling pathways to CD83 induction, we used pathway specific inhibitors. The NF-${\kappa}B$ inhibitor significantly reduced surface expression of CD83 as well as phagocytic activity of RAW 264.7 cells. Therefore, CD83 expression may contribute to the immunostimulatory effects of CpG-DNA in macrophage cells.

• Molecules and Cells
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• v.26 no.6
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• pp.606-610
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• 2008

Phenoloxidase (PO), a melanin-forming enzyme around the foreign bodies, is an important component of the host defense system in invertebrates. Pro-PO is the enzymatically inactive zymogen form of PO. In the Drosophila genome, three Pro-PO isoforms have been identified to date. These include Pro-PO1 and 2, which are primarily expressed in crystal cells, and Pro-PO3, which is predominantly found in the lamellocytes. In this study, we demonstrated that Drosophila Pro-PO3, but not Pro-PO1 or 2, is enzymatically active in its zymogen form. These findings were evidenced by spectacular melanin forming capacities of various cells and tissues that overexpressed these pro-enzymes. Furthermore, the melanization phenotype observed in the lamellocyte-enriched $hop^{Tum-l}$ mutant was drastically reduced in the absence of PPO3, indicating that PPO3 plays a major role in the lamellocyte-mediated spontaneous melanization process. Taken together, these findings indicate that the biochemical properties, activation mode and in vivo role of Pro-PO3 are likely distinct from those of the other two Pro-PO enzymes involved in Drosophila physiology.

• Journal of Microbiology and Biotechnology
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• v.20 no.11
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• pp.1585-1591
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• 2010

A comprehensive study on the production of inflammatory mediators in the lungs of BALB/c mice following infection with Stenotrophomonas maltophilia was conducted. The levels of pro-inflammatory cytokines, tumor necrosis factor alpha (TNF-${\alpha}$), and interleukin-1${\beta}$ (IL-1${\beta}$) were raised in the lungs of infected mice compared with control. The production of anti-inflammatory cytokine IL-10 was slightly delayed. Its peak level was on the $2^{nd}$ day, whereas the peak of pro-inflammatory cytokines was observed on day 1 after intranasal challenge. This was accompanied by a rise in myeloperoxidase (MPO) and malondialdehyde (MDA) on day 1. The increase in MPO levels matched with histopathological observations, as neutrophils infiltration was detected on the first day. Alveolar macrophages (AMs) obtained from infected animals showed a higher rate of uptake and killing when exposed to bacteria in vitro, compared with similar experiments conducted with AMs from normal mice (control). This suggests that AMs were more efficient in cleaning the bacteria. The nitric oxide (NO) production however started early during infection but reached its maximum on the $3^{rd}$ day. No mortality was observed among the infected animals, and infection was resolved by the $5^{th}$ day post infection. No drastic changes in the lung tissue were observed on histopathological examination.

• BMB Reports
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• v.40 no.1
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• pp.1-6
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• 2007

Apoptosis signal-regulating kinase 1 (ASK1) is a mitogenactivated protein kinase (MAPK) kinase kinase that activates JNK and p38 kinases. ASK1 is activated by various stresses, such as reactive oxygen species (ROS), endoplasmic reticulum (ER) stress, lipopolysaccharide (LPS) and calcium influx which are thought to be responsible for the pathogenesis or exacerbations of various human diseases. Recent studies revealed the involvement of ASK1 in ROS- or ER stressrelated diseases, suggesting that ASK1 may be a potential therapeutic target of various human diseases. In this review, we focus on the current findings for the relationship between pathogenesis and ASK1-MAPK pathways.

• BMB Reports
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• v.42 no.8
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• pp.506-510
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• 2009

The Toll signalling pathway in invertebrates is responsible for defense against Gram-positive bacteria and fungi, leading to the expression of antimicrobial peptides via NF-$\kappa$B-like transcription factors. Gram-negative binding protein 3 (GNBP3) detects beta-1,3-glucan, a fungal cell wall component, and activates a three step serine protease cascade for activation of the Toll signalling pathway. Here, we showed that the recombinant N-terminal domain of Tenebrio molitor GNBP3 bound to beta-1,3-glucan, but did not activate down-stream serine protease cascade in vitro. Reversely, the N-terminal domain blocked GNBP3-mediated serine protease cascade activation in vitro and also inhibited beta-1,3-glucan-mediated antimicrobial peptide induction in Tenebrio molitor larvae. These results suggest that the N-terminal GNBP homology domain of GNBP3 functions as a beta-1,3-glucan binding domain and the C-terminal domain of GNBP3 may be required for the recruitment of immediate down-stream serine protease zymogen during Toll signalling pathway activation.

• BMB Reports
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• v.47 no.7
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• pp.382-387
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• 2014

Corn silk (CS) has long been consumed as a traditional herb in Korea. Maysin is a major flavonoid of CS. The effects of maysin on macrophage activation were evaluated, using the murine macrophage RAW 264.7 cells. Maysin was isolated from CS by methanol extraction, and preparative $C_{18}$ reverse phase column chromatography. Maysin was nontoxic up to $100{\mu}g/ml$, and dose-dependently increased TNF-${\alpha}$ secretion and iNOS production by 11.2- and 4.2-fold, respectively, compared to untreated control. The activation and subsequent nuclear translocation of NF-${\kappa}B$ was substantially enhanced upon treatment with maysin ($1-100{\mu}g/ml$). Maysin also stimulated the phosphorylation of Akt and MAPKs (ERK, JNK). These results indicated that maysin activates macrophages to secrete TNF-${\alpha}$ and induce iNOS expression, via the activation of the Akt, NF-${\kappa}B$ and MAPKs signaling pathways. These results suggest for the first time that maysin can be a new immunomodulator, enhancing the early innate immunity.

• IMMUNE NETWORK
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• v.11 no.6
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• pp.406-411
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• 2011

Background: Invariant Natural killer T (iNKT) cells, a distinct subset of CD1d-restricted T cells with invariant $V{\alpha}{\beta}$ TCR, functionally bridge innate and adaptive immunity. While iNKT cells share features with conventional T cells in some functional aspects, they simultaneously produce large amount of Th1 and Th2 cytokines upon T-cell receptor (TCR) ligation. However, gene expression pattern in two types of cells has not been well characterized. Methods: we performed comparative microarray analyses of gene expression in murine iNKT cells and conventional $CD4^+CD25^-$ ${\gamma}{\delta}TCR^-$ T cells by using Gene Set Enrichment Analysis (GSEA) method. Results: Here, we describe profound differences in gene expression pattern between iNKT cells and conventional $CD4^+CD25^-$ ${\gamma}{\delta}TCR^-$ T cells. Conclusion: Our results provide new insights into the functional competence of iNKT cells and a better understanding of their various roles during immune responses.