• BMB Reports
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• 제42권2호
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• pp.72-80
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• 2009

In mammals, major progress has recently been made with the dissection of early embryonic cell specification, the isolation of stem cells from early embryos, and the production of embryonic-like stem cells from adult cells. These studies have overcome long-standing species barriers for stem cell isolation, have revealed a deeper than expected similarity of embryo cell types across species, and have led to a better understanding of the lineage identities of embryo-derived stem cells, most notably of mouse and human embryonic stem (ES) cells. Thus, it has now become possible to propose a species-overarching classification of embryo stem cells, which are defined here as pre- to early post-implantation conceptus-derived stem cell types that maintain embryonic lineage identities in vitro. The present article gives an overview of these cells and discusses their relationships with each other and the conceptus. Consequently, it is debated whether further embryo stem cell types await isolation, and the study of the earliest extraembryonically committed stem cells is identified as a promising new research field.

• 한국수정란이식학회지
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• 제27권3호
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• pp.189-192
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• 2012

Although embryonic stem cells (ESCs) or ES-like cells are reported from many mammalian species other than the mouse, the culture system for murine ESCs may not be suitable to the other species. Previously many other research groups have modified either human or mouse ESC culture systems for bovine ESC culture. In this study, we compared three different culture mediums consisting of DMEM, ${\alpha}$-MEM or KnockOut$^{TM}$-DMEM (KO), which are modified from human or mouse ESC culture system, for the generation of bovine ESCs. In this study, some pre-requisite events which are important for establishment and long-term propagation of ESCs such as inner cell mass (ICM) attachment on feeder cells, primary colony formation and sustainability after passaging. Once the ICM clumps attached on feeder cells, this was designated as passage 0. In regards to the rate of ICM attachment, ${\alpha}$-MEM was superior to the other systems. For primary colony formation, there was no difference between DMEM and ${\alpha}$-MEM whereas KO showed lower formation rate than the other groups. For passaging, the colonies were split into 2~4 pieces and passed every 5~6 days. From passage 1 to passage 3, DMEM system seemed to be appropriate for maintaining putative bovine ESCs. On the other hand, ${\alpha}$-MEM tended to be more suitable after passage 6. Although ${\alpha}$-MEM support to maintain a ES-like cell progenies to passage 15, all three culture systems which are modified from human or mouse ESC culture media failed to retain the propagation and long-term culture of putative bovine ESCs. Our findings imply that more optimized alternative culture system is required for establishing bovine ESC lines.

• Preventive Nutrition and Food Science
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• 제20권4호
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• pp.221-229
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• 2015

Hesperidin has been shown to possess a potential inhibitory effect on vascular formation in endothelial cells. However, the fundamental mechanism for the anti-angiogenic activity of hesperidin is not fully understood. In the present study, we evaluated whether hesperidin has anti-angiogenic effects in mouse embryonic stem cell (mES)-derived endothelial-like cells, and human umbilical vascular endothelial cells (HUVECs), and evaluated their mechanism via the AKT/mammalian target of rapamycin (mTOR) signaling pathway. The endothelial cells were treated with several doses of hesperidin (12.5, 25, 50, and $100{\mu}M$) for 24 h. Cell viability and vascular formation were analyzed using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide and tube formation assay, respectively. Alteration of the AKT/mTOR signaling in vascular formation was analyzed by western blot. In addition, a mouse aortic ring assay was used to determine the effect of hesperidin on vascular formation. There were no differences between the viability of mES-derived endothelial-like cells and HUVECs after hesperidin treatment. However, hesperidin significantly inhibited cell migration and tube formation of HUVECs (P<0.05) and suppressed sprouting of microvessels in the mouse aortic ring assay. Moreover, hesperidin suppressed the expression of AKT and mTOR in HUVECs. Taken together, these findings suggest that hesperidin inhibits vascular formation by blocking the AKT/mTOR signaling pathways.

• 한국수정란이식학회:학술대회논문집
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• 한국수정란이식학회 2003년도 제3회 발생공학 국제심포지움 및 학술대회
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• pp.97-97
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• 2003

• 한국발생생물학회지:발생과생식
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• 제14권4호
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• pp.215-223
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• 2010

배아줄기세포를 이용한 형질전환동물의 제조는 유전자의 기능 연구에 필수적이다. 특히 유전자 파괴 생쥐는 유전자의 기능 연구뿐만 아니라 사람 질병 연구에 중요한 모델이 되어 왔다. 유전자 적중법(gene targeting)과 유전자 함정법(gene trapping)은 ES 세포에서 녹아웃(knockout) 생쥐를 제조하는 대표적인 방법이다. 20여 년 전 유전자 적중법과 함정법이 최초로 개발된 이후에 이 기술은 많은 변화를 거쳤다. 특히 상동재조합에 기초한 전통적 유전자 적중법은 대량 제조기반의 조건부 유전자 적중법의 개발로 이어졌고, 유전자 적중법 및 유전자 함정법의 장점 요소의 조합은 유전자를 파괴하는 범위를 넓혔고, 유전자 적중을 더욱 효율적으로 만들었다. 이런 기술은 특정 유전자를 표적으로 하는 다양한 종류의 돌연변이 형질전환동물을 제조할 수 있게 하여 포스트게놈 시대에 요구되는 전체 유전체의 기능 연구를 더욱 효과적으로 진행시켜 줄 것이다.

• Journal of Microbiology and Biotechnology
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• 제20권10호
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• pp.1430-1435
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• 2010

Two angiostatic fusion proteins (hAE and hEA), differing in tandem connection manners, were constructed from human angiostatin (hAS) and endostatin (hES) proteins. These fusion proteins were then evaluated for synergistic antiangiogenic properties. The 65 kDa secreted fusion proteins, expressed in Pichia pastoris, were verified by both mass analysis and Western blotting assay. Luciferase reorter gene assay, using a VEGF promoter, revealed that the angiostatin-endostatin fusion protein (hAE), and its corresponding fusion gene delivery on human microvascular endothelial cells (HMEC-1), resulted in a more potent synergistic antiangiogenic effect than the endostatin-angiostatin fusion protein (hEA). These results suggest that the orientation of the fusion genes in hAS and hES might be an important factor in the development of therapeutic proteins.

• Clinical and Experimental Reproductive Medicine
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• 제33권1호
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• pp.25-33
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• 2006

목 적: 본 연구에서는 착상전 생쥐 배아에서 분리한 할구를 이용하여 배아줄기세포주를 확립하고 그 효용성과 특성을 살펴보고자 하였다. 연구방법: 생쥐 (C57BL/6J)의 2- 또는 4-세포기 배아에서 투명대를 제거하고 할구를 분리하여 지지세포와 공동배양한 후 할구로부터 형성된 내세포괴를 분리하여 계대배양을 실시하였다. 계대배양 중인 세포주의 특성을 확인하기 위해 alkaline phosphatase 활성도와 표지 인자 및 관련 유전자 발현을 세포면역화학적 염색과 RT-PCR 방법으로 살펴보았다. 또한, 계대배양 중인 배아줄기 세포주의 염색체 분석을 실시하였다. 결 과: 전체적으로 2-세포기에서 분리한 할구와 4-세포기에서 분리한 할구에서 각각 3.0% (1/33)와 4.0% (1/25)의 효율로 배아줄기세포주를 확립할 수 있었다. 이는 4-세포기의 배아를 사용하였을 때의 16.7% (5/30)에 비해 현저하게 낮았다. 분리된 할구로부터 확립된 배아줄기세포주에서 SSEA-l 과 Oct-4의 발현을 관찰하였고, 이들에서 분화된 배아체에서 삼배엽성 분화 관련 유전자들의 발현도 확인할 수 있었다. 결 론: 본 연구에서는 동물모델을 이용하여 착상전 초기 배아에서 분리한 할구를 이용하여 배이줄기세포를 확립할 수 있음을 확인하였다. 지속적인 관련 연구를 통해 인간의 체외수정 및 배아이식술에서 배아의 파괴 또는 발생 능력에 손상을 주지 않고 새로운 인간 배아줄기세포주를 생산할 수 있는 방법을 개발하고 실용화할 수 있을 것으로 사료된다.

• 한국동물번식학회:학술대회논문집
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• 한국동물번식학회 2004년도 춘계학술발표대회
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• pp.273-273
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• 2004

This study was to examine in vitro neural cell differentiation pattern of the genetically modified human embryonic stem cells expressing tyrosine hydroxylase (TH). Human embryonic stem (hES, MB03) cell was transfected with cDNAs cording for TH. Successful transfection was confirmed by western immunoblotting. (omitted)

• 한국동물번식학회:학술대회논문집
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• 한국동물번식학회 2003년도 학술발표대회 발표논문초록집
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• pp.75-75
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• 2003

Since the establishment of embryonic stem cell, pluripotency of the cells was known to allow differentiation of the cells into various cell types consisting whole body. Several protocols have been developed to induce expression of specific genes.. However, no precise protocol that will generate a single type of the cells from stem cells has been reported. In order to produce cells suitable for transplantion into brain of PD animal model, which arouse due to a progressive degeneration of dopaminergic neurons in midbrain, human embryonic stem cell (hESC, MB03) was transfected with cDNAs cording for tyrosine hydroxylase (TH). Successful transfection was confirmed by western immunoblotting. Newly transfected cell line (TH#2/MB03) was induced to differentiate by the two neurogenic factors retinoic acid (RA) and b-FGF. Exp. I) Upon differentiation using RA/ascorbic acid (AA), embryoid bodies (EB, for 4days) derived from hES cells were exposed to RA (10$^{-6}$ M)/AA (50 mM) for 4 days, and were allowed to differentiate in N2 medium for 7, 14, 21, or 28 days. Exp. II) When bFGF was used, neuronal precursor cells were selected for 8 days in N2 medium after EB formation. After selection, cells were expanded at the presence of bFGF (20 ng/ml) for another 6 days followed by a final differentiation in N2 medium for 7, 14, 21 or 28 days. By indirect immunocytochemical studies, proportion of cells expressing NF200 increased rapidly from 20% at 7 days to 70 % at 28 days in RA/AA-treated group, while those cells expressing NF160 decreased from 80% at 7 days to 10% at 28 days upon differentiation in N2 medium. However, in differentiation by RA/AA treatment system, there was a significant increase in proportion of neuron maturity (73%) at day 14 after N2 medium. TH#2/MB03 cells expressing TH are >90% when matured at the absence of either bDNF or TGF-$\alpha$. These results suggested that TH#2/MB03 cells could be differentiated in vitro into mature neurons by RA/AA.

• Asian-Australasian Journal of Animal Sciences
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• 제13권5호
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• pp.587-594
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• 2000

At present embryonic stem (ES) cells with confirmed pluripotential properties are only available in the mouse. Recently, we were able to isolate, culture and genetically transform primordial germ cell (PGC)-derived cells from pig embryos and demonstrate their ability to contribute to chimera development in the pig. In order to determine whether the system we developed could be used to isolate embryonic germ (EG) cells from other mammalian species, we placed isolated PGCs from cattle, goats, rabbits and rats in culture. Briefly, PGCs were isolated from fetuses of cow (day 30-50), goat (day 25), rabbit (day 15-18) and rat (day 11-12), and plated on STO feeder cells in Dulbecco's modified Eagle's medium (DMEM): Ham's F10 medium (1:1) supplemented with 0.01 mM nonessential amino acids, 2 mM L-glutamine, 0.1 mM $\beta$ - mercaptoethnol, soluble recombinant human stem cell factor (SCF; 40ng/ml), human basic fibroblast growth factor (bFGF; 20ng/ml) and human leukemia inhibitory factor (LIF; 20ng/ml). For maintenance of the cells, colonies were passed to fresh feeders every 7-10 days. In all species tested, we were able to obtain and maintain colonies with ES-like morphology. Their developmental potential was tested by alkaline phosphatase (AP) staining and in vitro differentiation assay. For genetic transformation, cells were electroporated with a construct containing the green fluorescent protein (GFP) under the control of the cytomegalovirus (CMV) promoter. GFP-expressing colonies were detected in cattle, rabbits and rats. These results suggest that PGC-derived cells from cattle, goats, rabbits and rats can be isolated, cultured, and genetically transformed, and provide the basis for analyzing their developmental potential and their possible use for the precise genetic modification of these species.