• Toxicological Research
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• v.29 no.4
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• pp.221-227
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• 2013

Embryonic stem (ES) cells have potential for use in evaluation of developmental toxicity because they are generated in large numbers and differentiate into three germ layers following formation of embryoid bodies (EBs). In earlier study, embryonic stem cell test (EST) was established for assessment of the embryotoxic potential of compounds. Using EBs indicating the onset of differentiation of mouse ES cells, many toxicologists have refined the developmental toxicity of a variety of compounds. However, due to some limitation of the EST method resulting from species-specific differences between humans and mouse, it is an incomplete approach. In this regard, we examined the effects of several developmental toxic chemicals on formation of EBs using human ES cells. Although human ES cells are fastidious in culture and differentiation, we concluded that the relevancy of our experimental method is more accurate than that of EST using mouse ES cells. These types of studies could extend our understanding of how human ES cells could be used for monitoring developmental toxicity and its relevance in relation to its differentiation progress. In addition, this concept will be used as a model system for screening for developmental toxicity of various chemicals. This article might update new information about the usage of embryonic stem cells in the context of their possible ability in the toxicological fields.

• Reproductive and Developmental Biology
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• v.38 no.4
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• pp.137-142
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• 2014

A tremendous increase in the human population has put poultry industry under an increased pressure to meet steep increase in the demand. Poultry is contributing 25% of the total world's meat production and lesser cost of investment per bird makes it more suitable for the further breeding programmes. Major poultry diseases frequently lead to cardiac damage and cause huge economic losses to poultry industry due to mortality. The in vitro embryonic stem cell (ESC) technology has a futuristic approach for homogeneous populace of differentiated cells, for their further transplantations. During in vitro conditions the differentiated cell populace can be used in grafting and transplantation processes to regenerate damaged tissues. Therefore, the current study targeted the use of spermatogonial stem cells (SSCs) in the poultry production system through cardiac regeneration. The current study will also open new boulevard for the similar kind of research in other livestock species for the management of heart diseases.

• 대한생식의학회:학술대회논문집
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• 2004.06a
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• pp.73-74
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• 2004

• BMB Reports
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• v.53 no.8
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• pp.437-441
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• 2020

In accordance with requirements of the ICH S7B safety pharmacology guidelines, numerous next-generation cardiotoxicity studies using human stem cell-derived cardiomyocytes (CMs) are being conducted globally. Although several stem cell-derived CMs are being developed for commercialization, there is insufficient research to verify if these CMs can replace animal experiments. In this study, in vitro high-efficiency CMs derived from human embryonic stem cells (hESC-CMs) were compared with Sprague-Dawley rats as in vivo experimental animals, and primary cultured in vitro rat-CMs for cardiotoxicity tests. In vivo rats were administrated with two consecutive injections of 100 mg/kg isoproterenol, 15 mg/kg doxorubicin, or 100 mg/kg nifedipine, while in vitro rat-CMs and hESC-CMs were treated with 5 μM isoproterenol, 5 μM doxorubicin, and 50 μM nifedipine. We have verified the equivalence of hESC-CMs assessments over various molecular biological markers, morphological analysis. Also, we have identified the advantages of hESC-CMs, which can distinguish between species variability, over electrophysiological analysis of ion channels against cardiac damage. Our findings demonstrate the possibility and advantage of high-efficiency hESC-CMs as next-generation cardiotoxicity assessment.

• Development and Reproduction
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• v.17 no.4
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• pp.379-387
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• 2013

Embryonic stem (ES) cells can self-renew and differentiate to various cells depending on the culture condition. Although ES cells are a good model for cell type specification and can be useful for application in clinics in the future, studies on ES cells have many experimental restraints including low transfection efficiency and transgene expression. Here, we observed that transgene expression after transfection was enhanced by treatment with histone deacetylse (HDAC) inhibitors such as trichostatin A, sodium butyrate, and valproic acid. Transfection was performed using conventional transfection reagents with a retroviral vector encoding GFP under the control of CMV promoter as a reporter. Treatment of ES cells with HDAC inhibitors after transfection increased population of GFP positive cells up to 180% compared with untreated control. ES cells showed normal expression of stem cell markers after treatment with HDAC inhibitors. Transgene expression was further enhanced by modifying transfection procedure. GFP positive cells selected after transfection were proved to have the stem cell properties. Our improved protocol for enhanced gene delivery and expression in mouse ES cells without hampering ES cell properties will be useful for study and application of ES cells.

• 대한생식의학회:학술대회논문집
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• 2004.06a
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• pp.72-73
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• 2004

• BMB Reports
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• v.45 no.5
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• pp.299-304
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• 2012

The ubiquitin-proteasome system is a major proteolytic system for nonlysosomal degradation of cellular proteins. Here, we investigated the response of mouse embryonic stem (ES) cells under proteotoxic stress. Proteasome inhibitors induced expression of heat shock protein 70 (HSP70) in a concentration- and time-dependent manner, and also induced apoptosis of ES cells. Importantly, more apoptotic cells were observed in ES cells compared with other somatic cells. To understand this phenomenon, we further investigated the expression of HSP70 and pluripotent cell markers. HSP70 expression was more significantly increased in somatic cells than in ES cells, and expression levels of pluripotent cell markers such as Oct4 and Nanog were decreased in ES cells. These results suggest that higher sensitivity of ES cells to proteotoxic stress may be related with lower capacity of HSP70 expression and decreased pluripotent cell marker expression, which is essential for the survival of ES cells.

• International Journal of Stem Cells
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• v.16 no.2
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• pp.145-155
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• 2023

Background and Objectives: Embryologically, mesodermal development is closely related to the development of various organs such as muscles, blood vessels, and hearts, which are the main organs that make up the body. However, treatment for mesoderm developmental disorders caused by congenital or acquired factors has so far relied on surgery and drug treatment for symptom relief, and more fundamentally, treatment for mesoderm developmental disorders is needed. Methods and Results: In our study, microRNA (miRNA), which plays an important role in the mesoderm development process, was identified and the developmental function was evaluated. miRNAs consist of small nucleotides, which act as transcription factors that bind to the 3' untranslated region and suppressed target gene expression. We constructed the human embryonic stem cell (hESC) knockout cell line and analyzed the function and characteristics of miR-5739, which plays an important role in mesoderm lineage. miR-5739 acts as a transcription factor targeting SMA, Brachyury T, Hand1, which controls muscle proliferation and differentiation, and KDR gene, which regulates vessel formation in vitro. In vivo results suggest a role in regulating muscle proliferation and differentiation. Gene ontology analysis confirmed that the miR-5739 is closely related to genes that regulate muscle and vessel proliferation and differentiation. Importantly, abnormal expression of miR-5739 was detected in somatic cells derived from patients with congenital muscle disease. Conclusions: Our study demonstrate that miR-5739 gene function significantly affects transcriptional circuits that regulate muscle and vascular differentiation during embryonic development.

• International Journal of Oral Biology
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• v.37 no.4
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• pp.175-180
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• 2012

Skin-derived precursor cells (SKPs) are multipotent, sphere-forming and embryonic neural crest-related precursor cells that can be isolated from dermis. It is known that the properties of porcine SKPs can be enhanced by leukemia inhibitory factor (LIF) which is an essential factor for the generation of embryonic stem cells in mice. In our present study, to enhance or maintain the properties of murine SKPs, LIF was added to the culture medium. SKPs were treated with 1,000 IU LIF for 72 hours after passage 3. Quantitative real time RT-PCR was then performed to quantify the expression of the pluripotent stem cell specific genes Oct4, Nanog, Klf4 and c-Myc, and the neural crest specific genes Snai2 and Ngfr. The results show that the expression of Oct4 is increased in murine SKPs by LIF treatment whereas the level of Ngfr is decreased under these conditions. Interestingly, LIF treatment reduced Nanog expression which is also important for cell proliferation in adult stem cells and for osteogenic induction in mesenchymal stem cells. These findings implicate LIF in the maintenance of stemness in SKPs through the suppression of lineage differentiation and in part through the control of cell proliferation.

• Asian-Australasian Journal of Animal Sciences
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• v.24 no.1
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• pp.1-8
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• 2011

Large quantities of high-quality recipient oocytes with uniform cytoplasm are needed for research in the promising field of somatic cell nuclear transfer (SCNT) and embryonic stem cell research. In canines, however, it is difficult to obtain large quantities of oocytes because each donor produces a limited number of mature oocytes in vivo. Although in vitro maturation (IVM) is considered an alternative approach to oocyte production, this technique is still too rudimentary to be used for the production of highquality, uniform oocytes in large quantities. One technique for overcoming this difficulty is to use oocytes obtained from different species. This technique is known as interspecies SCNT (iSCNT). This review provides an overview of recent advances in canine - porcine interspecies SCNT.