• Asian Pacific Journal of Cancer Prevention
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• 제14권1호
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• pp.359-365
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• 2013

The high mobility group box 1 (HMGB1) protein is a multifunctional cytokine-like molecule that plays an important role in the pathogenesis of tumors. In this study, real-time polymerase chain reactions and Western blot assays indicated that HMGB1 transcriptional activity and protein level are increased in $Tax^+$-T cells (TaxP). To clarify the mechanisms, a series of HMGB1 deletion reporter plasmids (pHLuc1 to pHLuc6) were transfected into $Tax^-$-T cells (TaxN, Jurkat) and $Tax^+$-T cells (TaxP). We found that promoter activity in $Tax^+$-T cells to be higher than that in $Tax^-$-T cells, indicating a significant increase in pHLuc6. Bay11-7082 (NF-${\kappa}B$ inhibitor) treatment did not block the enhancing effect. Chromatin immunoprecipitation assays revealed that Tax was retained on a HMGB1 promoter fragment encompassing -1163 to -975. Bioinformatics analysis showed six characteristic cis-elements for CdxA, AP-1, AML-1a, USF, v-Myb, and C/EBP in the fragment in question. Mutation of cis-elements for C/EBP reduced significant HMGB1 promoter activity induced by Tax. These findings indicate that Tax enhances the expression of HMGB1 gene at the transcriptional level, possibly by interacting with C/EBP.

• IMMUNE NETWORK
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• 제9권2호
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• pp.58-63
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• 2009

Background: T cell immunoglobulin and mucin domain containing 3 protein (Tim-3) expressed on terminally differentiated Th1 cells plays a suppressive role in Th1-mediated immune responses. Recently, it has been shown that N-glycosylation affects the binding activity of the Tim-3-Ig fusion protein to its ligand, galectin-9, but the binding properties of non-glycosylated Tim-3 on $CD4^+CD25^+$T cells has not been fully examined. In this study, we produced recombinant Tim-3-Ig fusion proteins in different cellular sources and its N-glycosylation mutant forms to evaluate their binding activities to $CD4^+CD25^+$T cells. Methods: We isolated and cloned Tim-3 cDNA from BALB/C mouse splenocytes. Then, we constructed a mammalian expression vector and a prokaryotic expression vector for the Tim-3-Ig fusion protein. Using a site directed mutagenesis method, plasmid vectors for Tim-3-Ig N-glycosylation mutant expression were produced. The recombinant protein was purified by protein A sepharose column chromatography. The binding activity of Tim-3-Ig fusion protein to $CD4^+CD25^+$T cells was analyzed using flow cytometry. Results: We found that the nonglycosylated Tim-3-Ig fusion proteins expressed in bacteria bound to $CD4^+CD25^+$T cells similarly to the glycosylated Tim-3-Ig protein produced in CHO cells. Further, three N-glycosylation mutant forms (N53Q, N100Q, N53/100Q) of Tim-3-Ig showed similar binding activities to those of wild type glycosylated Tim-3-Ig. Conclusion: Our results suggest that N-glycosylation of Tim-3 may not affect its binding activity to ligands expressed on $CD4^+CD25^+$T cells.

• Molecules and Cells
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• 제21권1호
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• pp.104-111
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• 2006

Gene therapy with nonviral vectors using the suicide gene/prodrug activating system of herpes simplex virus type-1 thymidine kinase (HSV1-TK)/ganciclovir (GCV) is inefficient in killing malignant tumor cells due to two major factors: (a) an unsatisfactory bystander effect; (b) short-lived expression of the protein. To study the capacity of the protein transduction domain (PTD) of HIV-1 TAT protein to enhance HSV1-TK/GCV cancer gene therapy, we constructed three fusion proteins TAT-TK, TK-TAT and TK. TAT-TK retained as much enzyme activity as TK, whereas that of TK-TAT was much lower. TAT-TK can enter HepG2 cells and much of it is translocated to the nucleus. The transduced HepG2 cells are killed by exogenously added GCV and have bystander effects on untransduced HepG2 cells. Most importantly, the introduced recombinant protein is stable and remains functional for several days at least, probably because nuclear localization protects it from the cytoplasmic degradation machinery and provides access to the nuclear transcription machinery. Our results indicate that TAT fusion proteins traffic intercellularly and have enhanced stability and prodrug cell killing activity. We conclude that TAT has potential for enhancing enzyme prodrug treatment of liver cancers.

• Journal of Microbiology and Biotechnology
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• 제11권4호
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• pp.677-684
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• 2001

To isolate mutanse-producing bacteria, soil samples were collected from several areas in chonnam Province, South Korea. A total of 70 strains of actinomycetes were isolated from the soil samples. All isolated actinomycetes were inoculated on mutanase screening media to identify new bacterial strains producing mutanase activity. One strain in particular exhibited a strong mutanase-producing activity, and was identified as Microbispora rosea based on its morphological, cultural, and physiological characteristics, and also by 16S rDNA sequences.

• Journal of Microbiology and Biotechnology
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• 제26권3호
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• pp.627-636
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• 2016

The causative agent of pandemic cholera, Vibrio cholerae, infects the anaerobic environment of the human intestine. Production of cholera toxin (CT), a major virulence factor of V. cholerae, is highly induced during anaerobic respiration with trimethylamine N-oxide (TMAO) as an alternative electron acceptor. However, the molecular mechanism of TMAO-stimulated CT production is not fully understood. Herein, we reveal that CT production during anaerobic TMAO respiration is affected by glucose fermentation. When the seventh pandemic V. cholerae O1 strain N16961 was grown with TMAO and additional glucose, CT production was markedly reduced. Furthermore, an N16961 Δcrp mutant, devoid of cyclic AMP receptor protein (CRP), was defective in CT production during growth by anaerobic TMAO respiration, further suggesting a role of glucose metabolism in regulating TMAO-mediated CT production. TMAO reductase activity was noticeably decreased when grown together with glucose or by mutation of the crp gene. A CRP binding region was identified in the promoter region of the torD gene, which encodes a structural subunit of the TMAO reductase. Gel shift assays further confirmed the binding of purified CRP to the torD promoter sequence. Together, our results suggest that the bacterial ability to respire using TMAO is controlled by CRP, whose activity is dependent on glucose availability. Our results reveal a novel mechanism for the regulation of major virulence factor production by V. cholerae under anaerobic growth conditions.

• Biomolecules & Therapeutics
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• 제23권5호
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• pp.465-470
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• 2015

Chrysin is a 5,7-dihydroxyflavone and was recently shown to potently inhibit enterovirus 71 (EV71) by suppressing viral 3C protease ($3C^{pro}$ activity. In the current study, we investigated whether chrysin also shows antiviral activity against coxsackievirus B3 (CVB3), which belongs to the same genus (Enterovirus) as EV71, and assessed its ability to prevent the resulting acute pancreatitis and myocarditis. We found that chrysin showed antiviral activity against CVB3 at $10{\mu}M$, but exhibited mild cellular cytotoxicity at $50{\mu}M$, prompting us to synthesize derivatives of chrysin to increase the antiviral activity and reduce its cytotoxicity. Among four 4-substituted benzyl derivatives derived from C(5) benzyl-protected derivatives 7, 9-11 had significant antiviral activity and showed the most potent activity against CVB3 with low cytotoxicity in Vero cells. Intraperitoneal injection of CVB3 in BALB/c mice with $1{\times}10^6TCID_{50}$ (50% tissue culture infective dose) of CVB3 induced acute pancreatitis with ablation of acinar cells and increased serum CXCL1 levels, whereas the daily administration of 9 for 5 days significantly alleviated the pancreatic inflammation and reduced the elevation in serum CXCL1 levels. Collectively, we assessed the anti-CVB3 activities of chrysin and its derivatives, and found that among 4-substituted benzyl derivatives, 9 exhibited the highest activity against CVB3 in vivo, and protected mice from CVB3-induced pancreatic damage, simultaneously lowering serum CXCL1 levels.

• IMMUNE NETWORK
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• 제10권4호
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• pp.126-134
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• 2010

Background: $CD8^+$ T cells contribute to the clearance of Hepatitis B virus (HBV) infection and an insufficient $CD8^+$ T cell response may be one of the major factors leading to chronic HBV infection. Since the HBx antigen of HBV can up-regulate cellular expression of several immunomodulatory molecules, we hypothesized that HBx expression in hepatocytes might affect $CD8^+$ T cell activity. Methods: We analyzed the activation and apoptosis of $CD8^+$ T cells co-cultured with primary hepatocytes rendered capable of expressing HBx by recombinant baculovirus infection. Results: Expression of HBx in hepatocytes induced low production of $interferon-{\gamma}$ and apoptosis of CD8+ T cells, with no effect on CD8 T cell proliferation. However, transcriptional levels of H-2K, ICAM-1 and PD-1 ligand did not correlate with HBx expression in hepatocytes. Conclusion: Our results suggest that HBx may inhibit $CD8^+$ T cell response by regulation of $interferon-{\gamma}$ production and apoptosis.

• 약학회지
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• 제42권2호
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• pp.132-139
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• 1998

Currently, cancer is the primary cause of death and 50% of cancer patients are incurable by surgery, radiotherapy and chemotherapy. Therefore, immunotherpy is interested as the fourth remedy. Biological response modifier (BRM), such as organometallic compounds, glycoproteins, polysaccharides and other natural products. Is the one which can enhance the immune response against cancer cell. To develop new BRM from natural sources, we investigated 63 species Korean traditional medicines by observing the mitogenic activity to splenocytes, generation of activated killer cells and activation of macrophages. Finally, we selected 9 species including Angelicae gigantis Radix, Mori Cortex Radicis, Arisaematis Tuber, Salviae Radix, Cnidii Rhizoma, Ligusti Fructus, Pasoraliae Semen, Loranthi Ramulus, Ginseng Radix. Bioassay-guided fractionation and purification is undergoing.

• International Journal of Oral Biology
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• 제46권3호
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• pp.111-118
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• 2021

Periodontitis and periimplantitis are caused as a result of dental biofilm formation. This biofilm is composed of multiple species of pathogens. Therefore, controlling biofilm formation is critical for disease prevention. To inhibit biofilm formation, sugars can be used to interrupt lectin-involving interactions between bacteria or between bacteria and a host. In this study, we evaluated the effect of D-Arabinose on biofilm formation of putative periodontal pathogens as well as the quorum sensing activity and whole protein profiles of the pathogens. Crystal violet staining, confocal laser scanning microscopy, and scanning electron microscopy revealed that D-Arabinose inhibited biofilm formation of Porphyromonas gingivalis, Fusobacterium nucleatum, and Tannerella forsythia. D-Arabinose also significantly inhibited the activity of autoinducer 2 of F. nucleatum and the expression of representative bacterial virulence genes. Furthermore, D-Arabinose treatment altered the expression of some bacterial proteins. These results demonstrate that D-Arabinose can be used as an antibiofilm agent for the prevention of periodontal infections.

• IMMUNE NETWORK
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• 제21권3호
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• pp.21.1-21.22
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• 2021

Myeloid-derived suppressor cells (MDSCs) have strong immunosuppressive activity and are morphologically similar to conventional monocytes and granulocytes. The development and classification of these cells have, however, been controversial. The activation network of MDSCs is relatively complex, and their mechanism of action is poorly understood, creating an avenue for further research. In recent years, MDSCs have been found to play an important role in immune regulation and in effectively inhibiting the activity of effector lymphocytes. Under certain conditions, particularly in the case of tissue damage or inflammation, MDSCs play a leading role in the immune response of the central nervous system. In cancer, however, this can lead to tumor immune evasion and the development of related diseases. Under cancerous conditions, tumors often alter bone marrow formation, thus affecting progenitor cell differentiation, and ultimately, MDSC accumulation. MDSCs are important contributors to tumor progression and play a key role in promoting tumor growth and metastasis, and even reduce the efficacy of immunotherapy. Currently, a number of studies have demonstrated that MDSCs play a key regulatory role in many clinical diseases. In light of these studies, this review discusses the origin of MDSCs, the mechanisms underlying their activation, their role in a variety of clinical diseases, and their function in immune response regulation.