• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.32 no.4
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• pp.327-333
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• 2006

Future cell-based therapies such as tissue engineering will benefit from a source of autogenous pluripotent stem cells. There are embryonic stem cells (ESC) and autologous adult stem cells, two general types of stem cells potentilally useful for these applications. But practical use of ESC is limited due to potential problems of cell regulation and ethical considerations. To get bone marrow stem cells is relatively burden to patients because of pain, anesthesia requirement. The ideal stem cells are required of such as the following advantages: easy to obtain, minimal patient discomfort and a capability of yielding enough cell numbers. Adipose autologus tissue taken from intraoral fatty pad or abdomen may represent such a source. Our study designed to demonstrate the ability of human adipose tissue-derived stromal cells (hATSC) from human abdominal adipose tissue diffentiating into osteocyte and adipocyte under culture in vitro conditions. As a result of experiment, we identified stromal cell derived adipose tissue has the multilineage potentiality under appropriate culture conditions. And the adipose stromal cells expressed several mesenchymal stem cell related antigen (CD29, CD44) reactions. Secondary, we compared the culture results of a group of hATSC stimulated with TGF-${\beta}$1, bFGF with a hATSC group without growth factors to confirm whether cytokines have a important role of the proliferation in osteogenic differentiation. The role of cytokines such as TGF-${\beta}$1, bFGF increased hATSC's osteogenic differentiation especially when TGF-${\beta}$1 and bFGF were used together. These results suggest that adipose stromal cells with growth factors could be efficiently available for cell-based bone regeneration.

• Molecules and Cells
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• v.41 no.2
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• pp.110-118
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• 2018

The objective of this study was to induce the production of isthmic organizer (IsO)-like cells capable of secreting fibroblast growth factor (FGF) 8 and WNT1 from human embryonic stem cells (ESCs). The precise modulation of canonical Wnt signaling was achieved in the presence of the small molecule CHIR99021 ($0.6{\mu}M$) during the neural induction of human ESCs, resulting in the differentiation of these cells into IsO-like cells having a midbrain-hindbrain border (MHB) fate in a manner that recapitulated their developmental course in vivo. Resultant cells showed upregulated expression levels of FGF8 and WNT1. The addition of exogenous FGF8 further increased WNT1 expression by 2.6 fold. Gene ontology following microarray analysis confirmed that IsO-like cells enriched the expression of MHB-related genes by 40 fold compared to control cells. Lysates and conditioned media of IsO-like cells contained functional FGF8 and WNT1 proteins that could induce MHB-related genes in differentiating ESCs. The method for generating functional IsO-like cells described in this study could be used to study human central nervous system development and congenital malformations of the midbrain and hindbrain.

• Journal of the Korea Convergence Society
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• v.8 no.9
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• pp.199-209
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• 2017

This study was carried out to confirm a convergent research pattern and researchers' role in stem cell sector by social network analysis. Articles were extracted from 1996 to 2012 in PubMed, 515 authors of 270 embryonic stem cell and induced pluripotent stem cell articles and 1,515 authors of 580 adult stem cell and mesenchymal stem cell articles. Degree(D) and betweenness(B) centrality was measured and co-author network was generated for researcher's role. As a result, Core researcher and Intermediary researcher was identified in co-author network. Core researcher had high D. centrality, otherwise high B. centrality or not. Intermediary researcher for convergent research had high B. centrality and low D. centrality. Conclusively, co-author network will be used as objective data not only to find core researchers in subject area for improving achievement but also to select experts for research project evaluation.

• Reproductive and Developmental Biology
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• v.33 no.3
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• pp.133-137
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• 2009

Pluripotent embryonic stem (ES) cells isolated from inner cell mass (ICM) of blastocyst-stage embryos are capable of differentiating into various cell lineages and demonstrate germ-line transmission in experimentally produced chimeras. These cells have a great potential as tools for transgenic animal production, screening of newly-developed drugs, and cell therapy. Miniature pigs, selectively bred pigs for small size, offer several advantages over large breed pigs in biomedical research including human disease model and xenotransplantation. In the present study, factors affecting primary culture of somatic cell nuclear transfer blastocysts from miniature pigs for isolation of ES cells were investigated. Formation of primary colonies occurred only on STO cells in human ES medium. In contrast, no ICM outgrowth was observed on mouse embryonic fibroblasts (MEF) in porcine ES medium. Plating intact blastocysts and isolated ICM resulted in comparable attachment on feeder layer and primary colony formation. After subculture of ES-like colonies, two putative ES cell lines were isolated. Colonies of putative ES cells morphologically resembled murine ES cells. These cells were maintained in culture up to three passages, but lost by spontaneous differentiation. The present study demonstrates factors involved in the early stage of nuclear transfer ES cell isolation in miniature pigs. However, long-term maintenance and characterization of nuclear transfer ES cells in miniature pigs are remained to be done in further studies.

• The Korean Journal of Physiology and Pharmacology
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• v.24 no.6
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• pp.463-472
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• 2020

Direct reprogramming, also known as a trans-differentiation, is a technique to allow mature cells to be converted into other types of cells without inducing a pluripotent stage. It has been suggested as a major strategy to acquire the desired type of cells in cell-based therapies to repair damaged tissues. Studies related to switching the fate of cells through epigenetic modification have been progressing and they can bypass safety issues raised by the virus-based transfection methods. In this study, a protocol was established to directly convert fully differentiated fibroblasts into diverse mesenchymal-lineage cells, such as osteoblasts, adipocytes, chondrocytes, and ectodermal cells, including neurons, by means of DNA demethylation, immediately followed by culturing in various differentiating media. First, 24 h exposure of 5-azacytidine (5-aza-CN), a well-characterized DNA methyl transferase inhibitor, to NIH-3T3 murine fibroblast cells induced the expression of stem-cell markers, that is, increasing cell plasticity. Next, 5-aza-CN treated fibroblasts were cultured in osteogenic, adipogenic, chondrogenic, and neurogenic media with or without bone morphogenetic protein 2 for a designated period. Differentiation of each desired type of cell was verified by quantitative reverse transcriptase-polymerase chain reaction/western blot assays for appropriate marker expression and by various staining methods, such as alkaline phosphatase/alizarin red S/oil red O/alcian blue. These proposed procedures allowed easier acquisition of the desired cells without any transgenic modification, using direct reprogramming technology, and thus may help make it more available in the clinical fields of regenerative medicine.

• The Korean Journal of Physiology and Pharmacology
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• v.24 no.6
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• pp.441-452
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• 2020

In vivo animal models are limited in their ability to mimic the extremely complex systems of the human body, and there is increasing disquiet about the ethics of animal research. Many authorities in different geographical areas are considering implementing a ban on animal testing, including testing for cosmetics and pharmaceuticals. Therefore, there is a need for research into systems that can replicate the responses of laboratory animals and simulate environments similar to the human body in a laboratory. An in vitro two-dimensional cell culture model is widely used, because such a system is relatively inexpensive, easy to implement, and can gather considerable amounts of reference data. However, these models lack a real physiological extracellular environment. Recent advances in stem cell biology, tissue engineering, and microfabrication techniques have facilitated the development of various 3D cell culture models. These include multicellular spheroids, organoids, and organs-on-chips, each of which has its own advantages and limitations. Organoids are organ-specific cell clusters created by aggregating cells derived from pluripotent, adult, and cancer stem cells. Patient-derived organoids can be used as models of human disease in a culture dish. Biomimetic organ chips are models that replicate the physiological and mechanical functions of human organs. Many organoids and organ-on-a-chips have been developed for drug screening and testing, so competition for patents between countries is also intensifying. We analyzed the scientific and technological trends underlying these cutting-edge models, which are developed for use as non-animal models for testing safety and efficacy at the nonclinical stages of drug development.

• Polymer(Korea)
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• v.29 no.5
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• pp.423-432
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• 2005

Over last three decades, various biomaterials has been developed and applied in the biomedical market. The practical utilization of biomaterials depends on the study about an appropriate physical and biological response of biomaterials. The modification of biomaterials using various surface treatment methods has recently become an interesting topic in the field of surface engineering. A padient surface is the surface on which a gradually varying chemical composition exists along its length. A large number of research groups have been focused on the preparation of gradient surfaces. Such gradient surface is of particular interest for basic and applied studies of the interactions between biological species and surfaces since the effect of a selected property like wettability or chemical composition can be examined in a single experiment on one surface. The present review focuses on the preparation and characterization of various gradient surfaces, and their interactions with biological species.

• International Journal of Stem Cells
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• v.7 no.2
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• pp.108-117
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• 2014

Background and Objectives: Genomic imprinting is an inheritance phenomenon by which a subset of genes are expressed from one allele of two homologous chromosomes in a parent of origin-specific manner. Even though fine-tuned regulation of genomic imprinting process is essential for normal development, no other means are available to study genomic imprinting in human during embryonic development. In relation with this bottleneck, differentiation of human embryonic stem cells (hESCs) into specialized lineages may be considered as an alternative to mimic human development. Methods and Results: In this study, hESCs were differentiated into three lineage cell types to analyze temporal and spatial expression of imprinted genes. Of 19 imprinted genes examined, 15 imprinted genes showed similar transcriptional level among two hESC lines and two human induced pluripotent stem cell (hiPSC) lines. Expressional patterns of most imprinted genes were varied in progenitors and fully differentiated cells which were derived from hESCs. Also, no consistence was observed in the expression pattern of imprinted genes within an imprinting domain during in vitro differentiation of hESCs into three lineage cell types. Conclusions: Transcriptional expression of imprinted genes is regulated in a cell type- specific manner in hESCs during in vitro differentiation.

• Experimental and Molecular Medicine
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• v.50 no.12
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• pp.5.1-5.15
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• 2018

Targeting hair follicle regeneration has been investigated for the treatment of hair loss, and fundamental studies investigating stem cells and their niche have been described. However, knowledge of stem cell metabolism and the specific regulation of bioenergetics during the hair regeneration process is currently insufficient. Here, we report the hair regrowth-promoting effect of a newly synthesized novel small molecule, IM176OUT05 (IM), which activates stem cell metabolism. IM facilitated stemness induction and maintenance during an induced pluripotent stem cell generation process. IM treatment mildly inhibited mitochondrial oxidative phosphorylation and concurrently increased glycolysis, which accelerated stemness induction during the early phase of reprogramming. More importantly, the topical application of IM accelerated hair follicle regeneration by stimulating the progression of the hair follicle cycle to the anagen phase and increased the hair follicle number in mice. Furthermore, the stem cell population with a glycolytic metabotype appeared slightly earlier in the IM-treated mice. Stem cell and niche signaling involved in the hair regeneration process was also activated by the IM treatment during the early phase of hair follicle regeneration. Overall, these results show that the novel small molecule IM promotes tissue regeneration, specifically in hair regrowth, by restructuring the metabolic configuration of stem cells.

• Journal of Dental Anesthesia and Pain Medicine
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• v.19 no.2
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• pp.91-99
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• 2019

Background: The imbalance between osteoblasts and osteoclasts can lead to pathological conditions such as osteoporosis. It has been reported that opioid adversely affect the skeletal system, but it is inconsistent. Remifentanil is currently used as an adjuvant analgesic drug in general anesthesia and sedation. The aim of the present study was to investigate the effect of remifentanil on the osteoblast differentiation and mechanism involved in this effect. Methods: The C2C12 cells (mouse pluripotent mesenchymal cell line) were used as preosteoblast. Osteoblastic differentiation potency was determined by alkaline phosphatase (ALP) staining. C2C12 cell migration by remifentanil was evaluated using Boyden chamber migration assay. The expression of Runx2 and osterix was evaluated by RT-PCT and western blot analysis to investigate the mechanism involved in remifentanil-mediated osteoblast differentiation. Results: ALP staining showed that remifentanil increased significantly osteoblast differentiation. In Boyden chamber migration assay, C2C12 cell migration was increased by remifentanil. RT-PCR and western blot analysis showed that the expression of Runx2 and osterix was upregulated by remifentanil. Conclusions: We demonstrated that remifentanil increased osteoblast differentiation in vitro by upregulation of Runx2 and osterix expression. Therefore, remifentanil has the potential for assisting with bone formation and bone healing.