• IMMUNE NETWORK
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• v.2 no.4
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• pp.233-241
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• 2002

Background: Monoclonal antibodies (mAb) of rodent origin are produced with ease by hybridoma fusion technique, and have been successfully used as therapeutic reagents for humans after humanization by genetic engineering. However, utilization of these antibodies for therapeutic purpose has been limited by the fact that they act as immunogens in human body causing undesired side effects. So far, there have been several attempts to produce human mAbs for effective in vivo diagnostic or therapeutic reagents including the use of humanized xenomouse that is generated by mating knockout mice which lost Ig heavy and light chain genes by homologous recombination and transgenic mice having both human Ig heavy and light gene loci in their genome. Methods: Genomic DNA fragments of mouse Ig heavy and light chain were obtained from a mouse brain ${\lambda}$ genomic library by PCR screening and cloned into a targeting vector with ultimate goal of generating Ig knockout mouse. Results: Through PCR screening of the genomic library, three heavy chain and three light chain Ig gene fragments were identified, and restriction map of one of the heavy chain gene fragments was determined. Then heavy chain Ig gene fragments were subcloned into a targeting vector. The resulting construct was introduced into embryonic stem cells. Antibiotic selection of transfected cells is under the progress. Conclusion: Generation of xenomouse is particularly important in medical biotechnology. However, this goal is not easily achieved due to the technical difficulties as well as huge financial expenses. Although we are in the early stage of a long-term project, our results, at least, partially contribute the successful generation of humanized xenomouse in Korea.

• Development and Reproduction
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• v.17 no.1
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• pp.9-16
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• 2013

Coactivator-associated arginine methyltransferase 1 (CARM1) is included in the protein arginine methyltransferase (PRMT) family, which methylates histone arginine residues through posttranslational modification. It has been proposed that CARM1 may up-regulate the expression of pluripotency-related genes through the alteration of the chromatin structure. Mouse embryonic stem cells (mESCs) are pluripotent and have the ability to self-renew. The cells are mainly used to study the genetic function of novel genes, because the cells facilitate the transmission of the manipulated genes into target mice. Since the up-regulated methylation levels of histone arginine residue lead to the maintenance of pluripotency in embryos and stem cells, it may be suggested that CARM1 overexpressing mESCs elevate the expression of pluripotency-related genes in reconstituted embryos for transgenic mice and may resist the differentiation into trophectoderm (TE). We constructed a fusion protein by connecting CARM1 and 7X-arginine (R7). As a cell-penetrating peptide (CPP), can translocate CARM1 protein into mESCs. CPP-CARM1 protein was detected in the nuclei of the mESCs after a treatment of 24 hours. Accordingly, the expression of pluripotency-related genes was up-regulated in CPP-CARM1-treated mESCs. In addition, CPP-CARM1-treated mESC-derived embryoid bodies (EBs) showed an elevated expression of pluripotency-related genes and delayed spontaneous differentiation. This result suggests that the treatment of recombinant CPP-CARM1 protein elevates the expression of pluripotency-related genes of mESCs by epigenetic modification, and this protein-delivery system could be used to modify embryonic fate in reconstituted embryos with mESCs.

• Nutrition Research and Practice
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• v.7 no.6
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• pp.439-445
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• 2013

It has been shown that dysregulation of IGF-1 signaling is associated with tumor incidence and progression, whereas blockade of the signaling can effectively inhibit carcinogenesis. Although several mechanisms of anticancer activity of quercetin were proposed, molecular targets of quercetin have not been identified yet. Hence, we assessed the effect of quercetin on IGF-1 signaling inhibition in BK5.IGF-1 transgenic (Tg) mice, which over-expresses IGF-1 in the skin epidermis. A quercetin diet (0.02% wt/wt) for 20 weeks remarkably delayed the incidence of skin tumor by 2 weeks and reduced tumor multiplicity by 35% in a 7,12-dimethylbenz(a)anthracene (DMBA)-tetradecanoyl phorbol-13-acetate (TPA) two stage mouse skin carcinogenesis protocol. Moreover, skin hyperplasia in Tg mice was significantly inhibited by a quercetin supplementation. Further analysis of the MT1/2 skin papilloma cell line showed that a quercetin treatment dose dependently suppressed IGF-1 induced phosphorylation of the IGF-1 receptor (IGF-1R), insulin receptor substrate (IRS)-1, Akt and S6K; however, had no effect on the phosphorylation of PTEN. Additionally, the quercetin treatment inhibited IGF-1 stimulated cell proliferation in a dose dependent manner. Taken together, these data suggest that quercetin has a potent anticancer activity through the inhibition of IGF-1 signaling.

• BMB Reports
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• v.51 no.4
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• pp.165-166
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• 2018

Osteoarthritis (OA) is the most common form of arthritis and is a leading cause of disability with a large socioeconomic cost. OA is a whole-joint disease characterized by cartilage destruction, synovial inflammation, osteophyte formation, and subchondral bone sclerosis. To date, however, no effective disease-modifying therapies for OA have been developed. The estrogen-related receptors (ERRs), a family of orphan nuclear receptor transcription factors, are composed of $ERR{\alpha}$, $ERR{\beta}$, and $ERR{\gamma}$, which play diverse biological functions such as cellular energy metabolism. However, the role of ERRs in OA pathogenesis has not been studied yet. Among the ERR family members, $ERR{\gamma}$ is markedly upregulated in human and various models of mouse OA cartilage. Adenovirus-mediated overexpression of $ERR{\gamma}$ in the mouse knee joint tissue caused OA pathogenesis. Additionally, cartilage-specific $ERR{\gamma}$ transgenic (Tg) mice exhibited enhanced experimental OA. Consistently, $ERR{\gamma}$ in articular chondrocytes directly caused expression of matrix metalloproteinase (MMP) 3 and MMP13, which play a crucial role in cartilage destruction. In contrast, genetic ablation of Esrrg or shRNA-mediated Esrrg silencing in the joint tissues abrogated experimental OA in mice. These results collectively indicated that $ERR{\gamma}$ is a novel catabolic regulator of OA pathogenesis and can be used as a therapeutic target for OA.

• Molecules and Cells
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• v.41 no.5
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• pp.486-494
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• 2018

Recently, we have reported that animals with telomerase reverse transcriptase (TERT) overexpression exhibit reduced social interaction, decreased preference for novel social interaction and poor nest-building behaviors-symptoms that mirror those observed in human autism spectrum disorders (ASD). Overexpression of TERT also alters the excitatory/inhibitory (E/I) ratio in the medial prefrontal cortex. However, the effects of TERT overexpression on hippocampal-dependent learning and synaptic efficacy have not been investigated. In the present study, we employed electrophysiological approaches in combination with behavioral analysis to examine hippocampal function of TERT transgenic (TERT-tg) mice and FVB controls. We found that TERT overexpression results in enhanced hippocampal excitation with no changes in inhibition and significantly impairs long-term synaptic plasticity. Interestingly, the expression levels of phosphorylated CREB and phosphorylated $CaMKII{\alpha}$ were significantly decreased while the expression level of $CaMKII{\alpha}$ was slightly increased in the hippocampus of TERT-overexpressing mice. Our observations highlight the importance of TERT in normal synaptic function and behavior and provide additional information on a novel animal model of ASD associated with TERT overexpression.

• Journal of Life Science
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• v.23 no.6
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• pp.812-824
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• 2013

Reserpine, an anti-hypertensive drug, is able to positively modulate several phenotypes associated with $A{\beta}$ toxicity in a Caenorhabditis elegans model of Alzheimer's disease (AD). We investigated into the therapeutic effects of reserpine on mammalian neurodegenerative disorders, and found that significant alteration of the key factors influencing AD was detected in Tg2576 mice after reserpine treatment for 30 days. The aggressive behavior of Tg2576 mice was significantly improved upon reserpine treatment, whereas their social contact was consistently maintained. Furthermore, the levels of $A{\beta}$-42 peptide in the hippocampus of the brain and blood serum were lower in the reserpine-treated group than in the vehicle-treated group. Among g-secretase components, the expression levels of PS-2, Pen-2, and APH-1 were slightly lower in reserpine-treated Tg2576 mice, although a significant change in nicastrin (NCT) expression was not detected. Furthermore, the serum level of nerve growth factor (NGF) increased in reserpine-treated Tg2576 mice compared with vehicle-treated mice. Among down-stream effectors of the NGF receptor TrkA signaling pathway, reserpine treatment induced elevation of TrkA phosphorylation and reduction of ERK phosphorylation. In addition, in the NGF receptor $p75^{NTR}$ signaling pathway, the expression levels of $p75^{NTR}$ and Bcl-2 were enhanced in reserpine-treated Tg2576 mice compared with vehicle-treated mice, whereas the expression level of RhoA declined. Overall, these results suggest that reserpine can help relieve AD pathogenesis in Tg2576 mice through downregulation of $A{\beta}$-42 deposition, alteration of ${\gamma}$-secretase components, and regulation of NGF metabolism.

• Journal of Chest Surgery
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• v.43 no.6
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• pp.588-595
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• 2010

Background: Base on types of tumor, the types of expressed tumor is diverse and the difference in its expression rate is even more various. Due to such reasons an animal model is absolutely needed for a clinical research of lung cancer. The author attempted oncogenesis by cultivating a cell line of non-small cell carcinoma and then injecting it inside thoracic cavities of nude mice. The author conducted quantitative analyses of HER2/neu tumor gene - an epidermal growth factor receptor (EGFR) related to lung cancer, and TGF-${\beta}_1$, which acts as a resistance to cell growth inhibition and malignant degeneration. In order to investigate achievability of the oncogenesis, histological changes and the expression of cancer gene in case of orthotopic lung cancer is necessary. Material and Method: Among 20 immunity-free male BALB/c, five nude mice were selected as the control group and rest as the experimental group. Their weights ranged from 20 to 25 gm (Orient, Japan). After injection of lung cancer line (SW900 G IV) into the pleural cavity of nude mice, They were raised at aseptic room for 8 weeks. HER2/neu was quantitatively analyzed by separating serum from gathered blood via chemiluminiscent immunoassay (CLIA), and immunosandwitch method was applied to quantitatively analyze TGF-${\beta}_1$. SPSS statistical program (SPSS Version 10.0, USA) was implemented for statistical analysis. Student T test was done, and cases in which p-value is less than 0.05 were considered significant. Result: Even after lung cancer was formed in the normal control group or after intentionally injected lung cancer cell line, no amplification of HER2/neu gene showed reaction. However, the exact quantity of TGF-${\beta}_1$ was $28,490{\pm}8,549pg/mL$, and the quantity in the group injected with lung cancer cell was $42,362{\pm}14,449pg/mL$, meaning 1.48 times highly Significant (p<0.483). It proved that HER2/neu gene TGF-${\beta}_1$ had no meaningful interconnection. Conclusion: TGF-${\beta}_1$ gene expressed approximately 1.48 times amplification in comparison to the control group. The amplification of TGF-${\beta}_1$ meant somatic recuperation inhibition mechanism due to carcinogenesis in nude mice was definitely working. It may be implemented as a quantitative analysis that allows early detection of lung cancer in human body.

• Journal of Plant Biotechnology
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• v.35 no.1
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• pp.87-94
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• 2008

Porcine epidemic diarrhea virus (PEDV) is an infectious and highly contagious virus of swine. In order to develop the transgenic tobacco culture cells producing PEDV antigen protein, four vectors expressing PEDV spike protein (SP) gene under the control of a CaMV 35S promoter were constructed. Four fragments of the SP region of PEDV, SP1 (444 bp, 1487-1930 bp), SP2 (1.7 kb, 2300-3987 bp), SP3 (1.4 kb, 1559-2950 bp), and SP4 (2.6 kb, 9-2643 bp) were amplified by PCR and then C-MYC tag was fused to the end of each SP gene, respectively. These cassettes are inserted into the pCAMBIA2300 (named as 35S::SP1-M, 35S::SP2-M 35S::SP3-M, and 35S::SP4-M, respectively). Tobacco (cv. BY-2) cultured cells were transformed by co-cultivation with Agrobacterium tumefaciens harboring expression vector. We selected kanamycin-resistant calli and checked for the presence of the introduced SP gene using PCR, resulting 70% of them showed the foreign gene. We selected the lines with high-level expression of PEDV antigen protein based on dot blot analysis. Southern blot analysis confirmed that the PEDV SP gene was integrated into the genome of the tobacco cultured cells. Northern blot analysis showed that the introduced gene was highly expressed in transgenic cultured cells. Transgenic tobacco cultured cells-derived antigen induced immunogenicity in mice as determined by a plaque reduction neutralization assay. These results suggest that the vectors expressing PEDV spike protein gene in this study will be useful for the development of transgenic plants and cultured cells producing PEDV antigene protein.

• Proceedings of the Korean Society of Applied Pharmacology
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• 1994.04a
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• pp.129-130
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• 1994

The science of toxicology is the understanding of the mechanisms by which exogenous agents produce deleterious effects in biological systems. The actions of chemicals such as drugs are ultimately exerted at the cellular and gene levels. Over the past decade. several in vitro alternative methods such as cultured cells for assessing the toxicity of various xenobiotics have been proposed to reduce the use of animals. In this workshop three advanced methods will be presented. These methods are novel important models for toxicologic studies. Dr. Tabuchis group has establishcd two immortalized gastric surface mucosa cell lines from the pminary cultore of gastric fundic mucosal cells of adult transgenic mice harboring a temperature sensitive simian virus 40 large T-anugen gene. As the immortalized cell lines of various tissues possess unique characteristics to maintain their normal functions for several months, these cell lines are extremely useful for not only toxicity testing but also pharmacological screening in new drug development. Professor Funatsu have studied the formation of spherical multicelluar aggregates of adult rat hepatocytes(spheroid) having tissue like structure. The sphcroid shown thre is a prototype module of an artificial liver support system. Thus, the urea synthesis activity of the artificial liver was maintained at least to days in 100％ rat blood plasma. Dr. Takezawa and his coworkers have developed a novel culture system of multicellular spheroids considered 〃organoids〃 by utilizing a thermo-responsive polymer as a substratum of anchorage dependent cells. His final goal is to reconstitute the organoids of various normal organs, e.g., liver, skin etc. and also abnormal deseased organs such as tumor.

• BMB Reports
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• v.42 no.5
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• pp.245-259
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• 2009

The process by which adult neural stem cells generate new and functionally integrated neurons in the adult mammalian brain has been intensely studied, but much more remains to be discovered. It is known that neural progenitors progress through distinct stages to become mature neurons, and this progression is tightly controlled by cell-cell interactions and signals in the neurogenic niche. However, less is known about the cell-intrinsic signaling required for proper progression through stages of adult neurogenesis. Techniques have recently been developed to manipulate genes specifically in adult neural stem cells and progenitors in vivo, such as the use of inducible transgenic mice and viral-mediated gene transduction. A critical mass of publications utilizing these techniques has been reached, making it timely to review which molecules are now known to play a cell-intrinsic role in regulating adult neurogenesis in vivo. By drawing attention to these isolated molecules (e.g. Notch), we hope to stimulate a broad effort to understand the complex and compelling cascades of intrinsic signaling molecules important to adult neurogenesis. Understanding this process opens the possibility of understanding brain functions subserved by neurogenesis, such as memory, and also of harnessing neural stem cells for repair of the diseased and injured brain.