• Reproductive and Developmental Biology
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• v.36 no.1
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• pp.21-26
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• 2012

Suspension culture is a useful tool for culturing embryonic stem (ES) cells in large-scale, but the stability of pluripotency and karyotype has to be maintained $in$ $vitro$ for clinical application. Therefore, we investigated whether the chromosomal abnormality of ES cells was induced in suspension culture or not. The ES cells were cultured in suspension as a form of aggregate with or without mouse embryonic fibroblasts (MEFs), and 0 or 1,000 U/ml leukemia inhibitory factor (LIF) was treated to suspended ES cells. After culturing ES cells in suspension, their karyotype, DNA content, and properties of pluripotency and differentiation were evaluated. As a result, the formation of tetraploid ES cell population was significantly increased in suspension culture in which ES cells were co-cultured with both MEFs and LIF. Tetraploid ES cell population was also generated when ES cells were cultured alone in suspension regardless of the existence of LIF. On the other hand, the formation of tetraploid ES cell population was not detected in LIF-free condition, in which MEFs were included. The origin of tetraploid ES cell population was turned out to be E14 ES cells and not MEFs by microsatellite analysis and the basic properties of them were still maintained despite ploidy-conversion to tetraploidy. Furthermore, we identified the ploidy shift from tetraploidy to near-triploidy as tetraploid ES cells were differentiated spontaneously. From these results, we demonstrated that suspension culture system could induce ploidy-conversion generating tetraploid ES cell population. Moreover, optimization of suspension culture system may make possible mass-production of ES cells.

• Proceedings of the KSAR Conference
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• 2003.06a
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• pp.30-30
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• 2003

The present study examined the developmental ability of embryonic stem (ES) cells aggregated with mouse parthenogenetic embryos. Oocytes obtained from superovulated female mouse (BCF1) were treated with 7% ethanol and 5 $\mu\textrm{g}$/$m\ell$ cytochalasin B (CB) for producing pathenotes and in vitro fertilized with fresh sperm for producing normal embryos. The reporter vector (pNeoEGFP) were inserted into ES cells (129S4/svJae) by electroporation. At the 8-cell stage, in vitro fertilized embryos and pathenotes, which the zona pellucida was removed, were co-cultured with 5~10 ES cells for 4 hr. After in vitro fertilized embryos and parthenotes aggregated with ES cells were incubated to blastocyst stage, and these blastocysts transferred into the uterus of pseudopregnant recipients. The fertilized embryos aggregated with ES cells were successfully developed to offspring, but the parthenotes aggregated with ES cells failed to develop offsprings. However, genomic DNA of ES cells was detected in the pathenogenetic fetus by polymerase chain reactions at 15 day post gestation. In this study, results indicated that parthenotes aggregated with ES cells showed possible development to fetus. In the future, this method may help to produce transgenic chimera from parthenotes aggregated with ES cells.

• Reproductive and Developmental Biology
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• v.31 no.4
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• pp.221-226
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• 2007

Embryonic stem (ES) cells are known to have an infinite proliferation and pluripotency that are associated with complex processes. The objective of this study was to examine expression of genes differentially regulated during differentiation of human ES cells by suppression subtractive hybridization (SSH). Human ES cells were induced to differentiate into neural precursor cells via embryoid body. Neural precursor cells were isolated physically based on morphological criteria. Immunocytochemical analysis showed expression of pax6 in neural precursor cells, confirming that the isolated cells were neural precursor cells. Undifferentiated human ES cells and neural precursor cells were subject to the SSH. TPX2 (Targeting Protein for Xklp2 (Xenopus centrosomal kinesin-like protein 2)) was identified, cloned and analyzed during differentiation of human ES cells into neural lineages. Expression of TPX2 was gradually down-regulated in embryoid bodies and neural precursor cells relative to undifferentiated ES cells. Targeting Protein for Xklp2 has been shown to be involved in cell division by interaction with microtubule development in cancer cells. Taken together, result of this study suggests that TPX2 may be involved in proliferation and differentiation of human ES cells.

• Korean Journal of Exercise Nutrition
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• v.24 no.3
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• pp.13-18
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• 2020

[Purpose] In vivo studies have demonstrated the ergogenic benefits of eleutherococcus senticosus (ES) supplementation. ES has been observed to enhance endurance capacity, improve cardiovascular function, and alter metabolic functions (e.g., increased fat utilization); however, the exact mechanisms involved remain unknown. We aimed to determine whether ES could effectively induce fat loss and improve muscle metabolic profiles through increases in lipolysis- and lipid metabolism-associated protein expression in 3T3-L1 adipocytes and C2C12 skeletal muscle cells, respectively, to uncover the direct effects of ES on adipocytes and skeletal muscle cells. [Methods] Different doses of ES extracts (0.2, 0.5, and 1.0 mg/mL) were added to cells (0.2 ES, 0.5 ES, and 1.0 ES, respectively) for 72 h and compared to the vehicle control (control). [Results] The intracellular triacylglycerol (TG) content significantly decreased (p < 0.05 for 0.2 ES, p < 0.01 for 0.5 ES and 1.0 ES) in 3T3-L1 cells. Adipose triglyceride lipase, which is involved in active lipolysis, was significantly higher in the 1.0 ES group than in the control group (p < 0.01) of 3T3-L1 adipocytes. In C2C12 cells, the mitochondrial protein voltage-dependent anion channel (VDAC) was significantly increased in the 1.0 ES group (p < 0.01). Furthermore, we found that 1.0 ES activated both 5' AMP-activated protein kinase (AMPK) and acetyl-CoA carboxylase (ACC) in skeletal muscle cells (p < 0.01). [Conclusion] These findings suggest that ES extracts decreased TG content, presumably by increasing lipase in adipocytes and metabolism-associated protein expression as well as mitochondrial biogenesis in muscle cells. These effects may corroborate previous in vivo findings regarding the ergogenic effects of ES supplementation.

• Proceedings of the Korean Society of Developmental Biology Conference
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• 2003.10a
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• pp.60-60
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• 2003

Embryonic stem (ES) cells have property of self-renewal and can differentiate into the cells of all three primary germ layers. Recently, many growth factors, alteration of culture condition and gene modifications have been used to differentiate mouse and human ES cells into specific cell types. This study was performed to evaluate the differentiation protocol for human ES cells to the endodermal lineage cells. Human ES cells (Miz-hESl ) were cultured on STO feeder layer mitotically inactivated with mitemycin C, and embryoid bodies (EBs) were formed by suspension culture. Differentiation protocol of EBs consisted of three steps: stage I, culture of EBs for 6 days with ITSFn medium; stage II, culture of stage I cells for 8 days with N2 medium ; stage III, culture of stage II cells for 22 days with N2 medium. mRNA levels of the endodermal lineage differentiation genes were analyzed by semi- quantitative RT-PCR. The Oct-4 expression, a marker of the pluripotent state, was detected in undifferentiated human ES cells but progressively decreased after EBs formation. Differentiating human ES cells expressed marker genes of endodermal differentiation and pancreatic islet cells. GATA4, a-fetoprotein, Glut-2, and Ngn3 were expressed in all stages. However, albumin and insulin were expressed in only stage III cells. The human ES cells can be differentiated into endodermal lineage cells by multiple step culture system using various supplements. We are developing the more effective protocols for guided differentiation of human ES cells.

• Korean Journal of Animal Reproduction
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• v.26 no.4
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• pp.377-384
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• 2002

To investigate the expression patterns of proteins and growth factor signals in differentiated rabbit embryonic stem (ES) cells, ES cells with confluent stage grown of feeder layer and differentiated cells into embryoid bodies (EB) without feeder cell were applied to protein gel and Western blotting analysis. There were 66kDa and 28kDa specifically expressed in differentiated ES cell but not in undifferentiated ES cell while 25kDa protein band showed up in only undifferentiated ES cells. Also there were some difference of protein bands in several area of gel between differentiated and undifferentiated ES cells such as about 100 kDa, 50kDa and 27kDa areas, but there was no difference in band pattern of one-dimensional gel analysis between mouse ES cells and rabbit ES cells. IGF-I receptor and EGF receptor were expressed in differentiated cells and undifferentiated cells. And ICF-I and EGF were not expressed in both differentiated and undifferentiated cells. These results indicated that ES cells express their own proteins to inhibit differentiation while EB cells synthesize different proteins to differentiate, and 16F-I receptor and EGF receptor were expressed in both ES and EB cells probably for the different functions.

• Microbiology and Biotechnology Letters
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• v.32 no.1
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• pp.11-15
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• 2004

Embryonic stem (ES) cells are derived from the inner cell mass of the blastocyst-stage embryos that can be propagated indefinitely and, at the same time, can be differentiated into all the cell types that constitute the body. Current research using ES cells is mainly focused on the efficient generation of specific cell types by employing optimal differentiation conditions, which often requires the genetic manipulation of ES cells. As a way of developing an efficient system to regulate foreign gene expression in ES cells, we have inserted the gene encoding Corynebacterium diphtheria toxin-A (DTA) into an autonomously induced plasmid under positive doxycycline control ('Tet-on' system). In this study, we demonstrate that this system can lead to the cell death of mouse ES cells by the induction of DTA expression when exposed to the tetracycline derivative, doxycycline. MTT assay showed that this induction resulted in the apoptosis of ES cells.

• Asian-Australasian Journal of Animal Sciences
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• v.24 no.1
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• pp.37-44
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• 2011

Parthenogenetic embryonic stem (pES) cells could provide a valuable model for research into genomic imprinting and X-linked diseases. In this study, pES cell lines were established from oocytes of hybrid offspring of Kunming and 129/Sv mice, and pluripotency of pES cells was evaluated. The pES cells maintained in the undifferentiated state for more than 50 passages had normal karyotypes with XX sex chromosomes and exhibited high activities of alkaline phosphatase (AKP) and telomerase. Meanwhile, these cells expressed ES cell molecular markers SSEA-1, Oct-4, Nanog, and GDF3 but not SSEA-3 detected by immunohistochemistry and RT-PCR. The pES cells could be differentiated into various types of cells from three germ layers in vitro by analysis of embryoid bodies (EBs) with immunohistochemistry and RT-PCR, and in vivo by observation of pES cell-derived teratoma sections. Therefore, the established pES cell lines contained all features of mouse ES cells. This work provides a new strategy for isolating pES cells from Kunming mice, and the pES cell lines could be applied as the cell model in research into genomic imprinting and epigenetic regulation of Kunming mice.

• Reproductive and Developmental Biology
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• v.30 no.1
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• pp.47-52
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• 2006

This study was conducted to examine whether the parthenogenetic mouse embryonic stem (P-mES) cells can differentiate into functional cardiomyocytes in vitro similar to (mES) cells. p-mES04 and IVF-derived mES03 cells were cultured by suspension culture for 4 days. The formed embryoid bodies (EBs) were treated with 0.75% dimethyl-sulfoxide (DMSO) for further 4 days (4-/4+), and then plated onto gelatin coated culture dish. The appearance of contracting cardiomyocytes from the P-mES04 and mES03 cells was examined for 30 days. The highest cumulative frequency was detected at days 13 (69.83%) and 22 (61.3%), respectively. By immunocytochemistry, beating P-mES04 cells were positively stained with muscle specific anti-sarcomeric a-actinin Ab and cardiac specific anti-cardiac troponin I Ab similar to contracted mES03 cells. When the expression of cardiac muscle-specific genes was analyzed by RT-PCR, beating P-mES04 cells were expressed cardiac specific L-type calcium channel, a1C, cardiac myosin heavy chain a, cardiac muscle heavy polypeptide $7{\beta}$, GATA binding protein 4 and atrial natriuretic factor, but not expressed skeletal muscle specific L-type calcium channel, a1S, which was similar to male adult heart cells and mES03-derived beating cardiomyocytes. The result demonstrates that the P-mES cells can be used as an alternative for the study on the characteristic analysis of in vitro cardiomyocyte differentiation from the ES cells.

• Clinical and Experimental Reproductive Medicine
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• v.29 no.2
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• pp.129-138
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• 2002

Objective: This study was to compare the characteristics between parthenogenetic mES (P-mES) cells and in vitro fertilization mES cells. Materials and Methods: Mouse oocytes were recovered from superovulated 4 wks hybrid F1 (C57BL/6xCBA/N) female mice. For parthenogenetic activation, oocytes were treated with 7% ethanol for 5 min and $5{\mu}g$/ml cytochalasin-B for 4 h. For IVF, oocytes were inseminated with epididymal sperm of hybrid F1 male mice ($1{times}10^6/ml$). IVF and parthenogenetic embryos were cultured in M16 medium for 4 days. Cell number count of blastocysts in those two groups was taken by differential labelling using propidium iodide (red) and bisbenzimide (blue). To establish ES cells, b1astocysts in IVF and parthenogenetic groups were treated by immunosurgery and recovered inner cell mass (ICM) cells were cultured in LIF added ES culture medium. To identify ES cells, the surface markers alkaline phosphatase, SSEA-1, 3,4 and Oct4 staining were examined in rep1ated ICM colonies. Chromosome numbers in P-mES and mES were checked. Also, in vitro differentiation potential of P-mES and mES was examined. Results: Although the cleavage rate (${\geq}$2-cell) was not different between IVF (76.3%) and parthenogenetic group (67.0%), in vitro development rate was significantly low in parthenogenetic group (24.0%) than IVF group (68.4%) (p<0.05). Cell number count of ICM and total cell in parthenogenetic b1astocysts ($9.6{\pm}3.1,\;35.1{\pm}5.2$) were signficantly lower than those of IVF blastocysts ($19.5{\pm}4.7,\;63.2{\pm}13.0$) (p<0.05). Through the serial treatment procedure such as immunosurgery, plating of ICM and colony formation, two ICM colonies in IVF group (mES, 10.0%) and three ICM colonies (P-mES, 42.9%) in parthenogenetic group were able to culture for extended duration (25 and 20 passages, respectively). Using surface markers, alkaline phosphatase, SSEA-l and Oct4 in P-mES and mES colony were positively stained. The number of chromosome was normal in ES colony from two groups. Also, in vitro neural and cardiac cell differentiation derived from mES or P-mES cells was confirmed. Conclusion: This study suggested that P-mES cells can be successfully established and that those cell lines have similar characteristics to mES cells.