• Molecules and Cells
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• v.25 no.4
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• pp.487-493
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• 2008

HoxB4 has been shown to enhance hematopoietic engraftment by hematopoietic stem cells (HSC) from differentiating mouse embryonic stem cell (mESC) cultures. Here we examined the effect of ectopic expression of HoxB4 in differentiated human embryonic stem cells (hESCs). Stable HoxB4-expressing hESCs were established by lentiviral transduction, and the forced expression of HoxB4 did not affect stem cell features. HoxB4-expressing hESC-derived CD34+ cells generated higher numbers of erythroid and blast-like colonies than controls. The number of CD34+ cells increased but CD45+ and KDR+ cell numbers were not significantly affected. When the hESC derived CD34+ cells were transplanted into $NOD/SCID{\beta}2m-/-$ mice, the ectopic expression of HoxB4 did not alter their repopulating capacity. Our findings show that overexpression of HoxB4 in differentiating hESCs increases hematopoietic colony formation and hematopoietic cell formation in vitro, but does not affect in vivo repopulation in adult mice hosts.

• Animal cells and systems
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• v.2 no.4
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• pp.521-527
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• 1998

The turnover of epidermal cells after seawater adaptation of the freshwater fishwas studied in the guppy (Poecilia reticulata) by means of Proliferating cell nucleus antigen (PCNA) immunocytochemistry and transmission electron microscopy. The number of PCNA-immunoreactive cells in the epidermis of the seawater-adapted guppies, which becomes thinner than that in the fresh-water, generally increases four times as much. Degeneration of filament-containing cells by necrosis or apoptosis occurs mainly in epidermal cells. Apoptotic filament-containing cells seem to be shed into the water in the environment instead of phagocytosis by adjacent macrophages. The apoptotic chloride cell has a highly condensed cytoplasm and the lumen of tubular system is distended. The apoptotic mucous cell, which has an electron-dense cytoplasm, is characterized by the presence of a large multivesicular body of different electron densities. Macrophages contain many electron-dense lysosomal bodies and large vesicles filled with cellular debris. It is concluded that mitosis and apoptosis of epidermal cells are greatly stimulated when fish are adapting to seawater. This result reflects an increase in epidermal cell turnover by change of environmental salinity.

• Proceedings of the Korea Crystallographic Association Conference
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• 2002.11a
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• pp.24-24
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• 2002

HtrA (high temperature requirement A), a periplasmic heat shock protein, is known to have molecular chaperone function at low temperatures and proteolytic activity at elevated temperatures. To investigate the mechanism of functional switch to pretense, we have determined the crystal structure of the N-terminal protease domain (PD) of HtrA from Thermotoga maritima. HtrA PD shares the same fold with chymotrypsin-like serine professes. However, crystal structure suggests that HtrA PD is not an active pretense at current state since its active site is not formed properly and blocked by an additional helical lid. On the surface of the lid, HtrA PD has hydrophobic patches that could be potential substrate binding sites for molecular chaperone activity. Present structure suggests that the activation of the proteolytic function of HtrA PD at elevated temperatures might occur by the conformational change.

• BMB Reports
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• v.52 no.7
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• pp.424-433
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• 2019

Autism spectrum disorder (ASD) is a complex neurodevelopmental monogenic disorder with a strong genetic influence. Idiopathic autism could be defined as a type of autism that does not have a specific causative agent. Among signalling cascades, mTOR signalling pathway plays a pivotal role not only in cell cycle, but also in protein synthesis and regulation of brain homeostasis in ASD patients. The present review highlights, underlying mechanism of mTOR and its role in altered signalling cascades as a triggering factor in the onset of idiopathic autism. Further, this review discusses how distorted mTOR signalling pathway stimulates truncated translation in neuronal cells and leads to downregulation of protein synthesis at dendritic spines of the brain. This review concludes by suggesting downstream regulators such as p70S6K, eIF4B, eIF4E of mTOR signalling pathway as promising therapeutic targets for idiopathic autistic individuals.

• BMB Reports
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• v.38 no.6
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• pp.755-762
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• 2005

Epstein-Barr virus (EBV) infects more than 90% of the world's population and has a potential oncogenic nature. A histone deacetylase (HDAC) inhibitor, trichostatin A (TSA), has shown potential ability in cancer chemoprevention and treatment, but its effect on EBV-infected Akata cells has not been examined. This study investigated the effect of TSA on the proliferation and apoptosis of the cells. TSA inhibited cell growth and induced cytotoxicity in the EBV infected Akata cells. TSA treatment sensitively induced apoptosis in the cell, which was demonstrated by the increased number of positively stained cells in the TUNEL assay, the migration of many cells to the sub-$G_0/G_1$ phase in flow cytometric analysis, and the ladder formation of genomic DNA. Western blot analysis showed that caspase-dependent pathways are involved in the TSA-induced apoptosis of EBV-infected Akata cells. Overall, this study shows that EBV-infected B lymphomas are quite sensitive to TSA-provoked apoptosis.

• Molecules and Cells
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• v.20 no.1
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• pp.136-141
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• 2005

Mild stresses such as high temperature ($30^{\circ}C$) or a low $H_2O_2$ concentration induced transient cell cycle arrest at G1/S or G2/M depending on the cell cycle stage at which the stress was applied. When stresses were introduced during G0 or G1, the G1/S checkpoint was mainly used; when stresses were introduced after S phase, G2/M was the primary checkpoint. The slowing of cell cycle progression was associated with transient delays in expression of A-, B-, and D-type cyclins. The delay in expression of NtcycA13, one of the A-type cyclins, was most pronounced. The levels of expression of Ntcyc29 (a cyclin B gene) and of CycD3-1 differed most depending on the applied stress, suggesting that different cellular adjustments to mild heat and a low concentration of $H_2O_2$ are reflected in the expression of these two cyclins.

• BMB Reports
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• v.51 no.8
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• pp.412-417
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• 2018

Homotypic cell-in-cell (CIC) structures forming between cancer cells were proposed to promote tumor evolution via entosis, a nonapoptotic cell death process. However, the mechanisms underlying their formation remained poorly understood. We performed a microarray analysis to identify genes associated with homotypic CIC formation. Cancer cells differing in their ability to form homotypic CIC structures were selected for the study. Association analysis identified 73 probe sets for 62 candidate genes potentially involved in CIC formation. Among them, twenty-one genes were downregulated while 41 genes were upregulated. Pathway analysis identified a gene interaction network centered on IL-8, which was upregulated in high CIC cells. Remarkably, CIC formation was significantly inhibited by IL-8 knockdown and enhanced upon recombinant IL-8 treatment, which correlated with altered cell-cell adhesion and expression of adhesive molecules such as P-cadherin and ${\gamma}$-catenin. Together, our work identified IL-8 as a positive regulator of homotypic CIC formation via enhancing intercellular adhesion.

• Fisheries and Aquatic Sciences
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• v.17 no.3
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• pp.385-390
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• 2014

Abalone immortal cell lines can be used to study the physiological properties and disease mechanisms of abalone at the cellular and molecular level. As a first step for the final goal to establish abalone immortal cell lines, we examined various initial culture conditions for primary cell populations derived from Haliotis discus hannai radula tissue. The survival rate after cell isolation procedures using the enzymatic method was as low as $9.95{\pm}2.37%$. Based on three different experimental conditions for H. discus hannai radula-derived cell culture, we found that the salinity of the media and the presence of growth-promoting factors were important to support radula-derived primary cell populations during the initial culture. The growth factor-containing media adjusted to 35 psu salinity could induce 100% (8 out of 8 trials) initial cell attachment, and the rate of cell attachment reached 50-70%. The data obtained from this study will provide useful information for developing immortal cell lines from abalone species.

• BMB Reports
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• v.50 no.2
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• pp.97-102
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• 2017

Patients with inflammatory bone disease or cancer exhibit an increased risk of fractures and delayed bone healing. The S100A4 protein is a member of the calcium-binding S100 protein family, which is abundantly expressed in inflammatory diseases and cancers. We investigated the effects of extracellular S100A4 on osteoblasts, which are cells responsible for bone formation. Treating primary calvarial osteoblasts with recombinant S100A4 resulted in matrix mineralization reductions. The expression of osteoblast marker genes including osteocalcin and osterix was also suppressed. Interestingly, S100A4 stimulated the nuclear factor-kappaB (NF-${\kappa}B$) signaling pathway in osteoblasts. More importantly, the ex vivo organ culture of mouse calvariae with recombinant S100A4 decreased the expression levels of osteocalcin, supporting the results of our in vitro experiments. This suggests that extracellular S100A4 is important for the regulation of bone formation by activating the NF-${\kappa}B$ signaling pathway in osteoblasts.

• International Journal of Oral Biology
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• v.30 no.4
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• pp.143-148
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• 2005

Osteoclasts are multinucleated cells with bone resorbing activity and differentiated from hematopoietic cell lineages of monocyte/macrophages in the presence of receptor activator of NF-${\kappa}B$ ligand (RANKL) and M-CSF. However, the exact molecular mechanisms through which RANKL stimulates osteoclastogenesis remain to be elucidated. Here we report that activation of cAMP-response elementbinding protein (CREB) is not involved in osteoclastogenesis from osteoclast precursors in response to RANKL. RANKL induced CREB activation in osteoclast precursors. Using pharmacological inhibitors, we found that RANKL-induced CREB activation is dependent on p38 MAPK pathways. We also found that ectopic expressions of wild type and dominant negative forms of CREB in osteoclast precursors did not affect RANKL-induced osteoclast formation and bone resorbing activity. Furthermore, dominant negative forms of CREB did not alter the expression levels of osteoclast-specific marker genes. Taken together, these data suggest that CREB is dispensable for differentiation and resorbing activity of osteoclasts.