• Korean Journal of Otorhinolaryngology-Head and Neck Surgery
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• 제56권12호
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• pp.749-753
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• 2013

Basically stem cells have characteristics of multi-potency, differentiation into multiple tissue types, and self-renew through proliferation. Recent advances in stem cell biology can make identifying the stem-cell like cells in various mammalian tissues. Stem cells in various tissues can restore damaged tissue. Stem cells from the adult nervous system proliferate to form clonal floating colonies called spheres in vitro, and recent studies have demonstrated sphere formation by cells in the tympanic membrane, vestibular system, spiral ganglion, and partly in the organ of Corti. The presence of stem cells in the ear raises the possibilities for the regeneration of the tympanic membrane & inner ear hair cells & neurons. But the gradual loss of stem cells postnatally in the organ of Corti may correlate with the loss of regenerative capacity and limited hearing restoration. Future strategies using endogenous stem cells in the ear can be the another treatment modality for the patients with intractable inner ear diseases.

• 대한의생명과학회지
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• 제19권4호
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• pp.295-302
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• 2013

Some of the pituitary adenomas are invasive and spread into neighboring tissues. In previous studies, the invasion of pituitary adenomas is thought to be associated with epithelial-mesenchymal transition (EMT). In addition to that, we thought that mesenchymal stem cells (MSCs) exist in relevant microenvironment in pituitary adenoma. However, it has been little known about the existence of MSCs from pituitary adenoma. So we investigated whether mesenchymal stem-like cells (MSLCs) can be isolated from the pituitary adenoma specimen. We isolated and cultured candidate MSLCs from the fresh pituitary adenoma specimen with the same protocols used in culturing bone marrow derived MSCs (BM-MSCs). The cultured candidate MSLCs were analyzed by fluorescence-activated cell sorting (FACS) for surface markers associated with MSCs. Candidate MSLCs were exposed to mesenchymal differentiation conditions to determine the mesenchymal differentiation potential of these cells. To evaluate the tumorigenesis of candidate MSLCs from pituitary adenoma, we implanted these cells into the brain of athymic nude mice. We isolated cells resembling BM-MSCs named pituitary adenoma stroma mesenchymal stem-like cells (PAS-MSLCs). PAS-MSLCs were spindle shaped and had adherent characteristics. FACS analysis identified that the PAS-MSLCs had a bit similar surface markers to BM-MSCs. Isolated cells expressed surface antigen, positive for CD105, CD75, and negative for CD45, NG2, and CD90. We found that these cells were capable of differentiation into adipocytes, osteocytes and chondrocytes. Tumor was not developed in the nude mice brains that were implanted with the PAS-MSLCs. In this study, we showed that MSLCs can be isolated from a pituitary adenoma specimen which is not tumorigenic.

• Restorative Dentistry and Endodontics
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• 제37권1호
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• pp.34-40
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• 2012

Objectives: The aim was to confirm the stem cell-like properties of the dental pulp stromal cells and to evaluate the morphologic changes during in vitro chondrogenesis. Materials and Methods: Stromal cells were outgrown from the dental pulp tissue of the premolars. Surface markers were investigated and cell proliferation rate was compared to other mesenchymal stem cells. Multipotency of the pulp cells was confirmed by inducing osteogenesis, adipogenesis and chondrogenesis. The morphologic changes in the chondrogenic pellet during the 21 day of induction were evaluated under light microscope and transmission electron microscope. TUNEL assay was used to evaluate apoptosis within the chondrogenic pellets. Results: Pulp cells were CD90, 105 positive and CD31, 34 negative. They showed similar proliferation rate to other stem cells. Pulp cells differentiated to osteogenic, adipogenic and chondrogenic tissues. During chondrogenesis, 3-dimensional pellet was created with multi-layers, hypertrophic chondrocyte-like cells and cartilage-like extracellular matrix. However, cell morphology became irregular and apoptotic cells were increased after 7 day of chondrogenic induction. Conclusions: Pulp cells indicated mesenchymal stem cell-like characteristics. During the in vitro chondrogenesis, cellular activity was superior during the earlier phase (within 7 day) of differentiation.

• 한국발생생물학회지:발생과생식
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• 제12권2호
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• pp.183-194
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• 2008

A variety of stem cells has been emerging as therapeutic cells that can replace organ transplantation in human liver diseases. The present study focused on whether human eyelid adipose-derived stem cells (HAD) might differentiate into functional hepatocyte-like cells in vitro. HAD were isolated from human eyelid adipose tissue. Effect of dimethyl sulfoxide (DMSO), fibroblast growth factor (FGF)-2 and FGF-4 on the hepatic differentiation of HAD have been examined in vitro. Immunocytochemical analysis and PAS staining showed that HAD cultured in both DMSO and FGF-4 exhibited the most intense staining than HAD of the other experimental groups. These HAD expressed numerous hepatocyte-related genes. Immunoblotting analyses showed that HAD cultured in the presence of DMSO and FGF-4 secreted higher amount of human albumin than HAD cultured in other conditions. Urea analysis also demonstrated that these HAD produced higher amount of urea than any other groups of HAD. In conclusion, combined treatment of DMSO and FGF-4 could effectively induce the functional differentiation of HAD into hepatocyte-like cells.

• IMMUNE NETWORK
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• 제20권1호
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• pp.2.1-2.19
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• 2020

Acute viral infection or vaccination generates highly functional memory CD8 T cells following the Ag resolution. In contrast, persistent antigenic stimulation in chronic viral infection and cancer leads to a state of T-cell dysfunction termed T-cell exhaustion. We and other have recently identified a novel subset of exhausted CD8 T cells that act as stem cells for maintaining virus-specific CD8 T cells in a mouse model of chronic lymphocytic choriomeningitis virus infection. This stem cell-like CD8 T-cell subset has been also observed in both mouse and human tumor models. Most importantly, in both chronic viral infection and tumor models, the proliferative burst of Ag-specific CD8 T cells driven by PD-1-directed immunotherapy comes exclusively from this stem cell-like CD8 T-cell subset. Therefore, a better understanding of the mechanisms how CD8 T-cell subsets are regulated during chronic viral infection and cancer is required to improve the current immunotherapies that restore the function of exhausted CD8 T cells. In this review, we discuss the differentiation of virus-specific CD8 T cells during chronic viral infection, the characteristics and function of CD8 T-cell subsets, and the therapeutic intervention of PD-1-directed immunotherapy in cancer.

• Molecules and Cells
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• 제40권6호
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• pp.386-392
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• 2017

Periodontal ligament stem cells (PDLSCs) are multipotent stem cells derived from periodontium and have mesenchymal stem cell (MSC)-like characteristics. Recently, the perivascular region was recognized as the developmental origin of MSCs, which suggests the in vivo angiogenic potential of PDLSCs. In this study, we investigated whether PDLSCs could be a potential source of perivascular cells, which could contribute to in vivo angiogenesis. PDLSCs exhibited typical MSC-like characteristics such as the expression pattern of surface markers (CD29, CD44, CD73, and CD105) and differentiation potentials (osteogenic and adipogenic differentiation). Moreover, PDLSCs expressed perivascular cell markers such as NG2, ${\alpha}-smooth$ muscle actin, platelet-derived growth factor receptor ${\beta}$, and CD146. We conducted an in vivo Matrigel plug assay to confirm the in vivo angiogenic potential of PDLSCs. We could not observe significant vessel-like structures with PDLSCs alone or human umbilical vein endothelial cells (HUVECs) alone at day 7 after injection. However, when PDLSCs and HUVECs were co-injected, there were vessel-like structures containing red blood cells in the lumens, which suggested that anastomosis occurred between newly formed vessels and host circulatory system. To block the $SDF-1{\alpha}$ and CXCR4 axis between PDLSCs and HUVECs, AMD3100, a CXCR4 antagonist, was added into the Matrigel plug. After day 3 and day 7 after injection, there were no significant vessel-like structures. In conclusion, we demonstrated the perivascular characteristics of PDLSCs and their contribution to in vivo angiogenesis, which might imply potential application of PDLSCs into the neovascularization of tissue engineering and vascular diseases.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제38권6호
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• pp.343-353
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• 2012

Objectives: This aim of this study was to effectively isolate mesenchymal stem cells (hSMSCs) from human submandibular skin tissues (termed hSMSCs) and evaluate their characteristics. These hSMSCs were then chemically induced to the neuronal lineage and analyzed for their neurogenic characteristics in vitro. Materials and Methods: Submandibular skin tissues were harvested from four adult patients and cultured in stem cell media. Isolated hSMSCs were evaluated for their multipotency and other stem cell characteristics. These cells were differentiated into neuronal cells with a chemical induction protocol. During the neuronal induction of hSMSCs, morphological changes and the expression of neuron-specific proteins (by fluorescence-activated cell sorting [FACS]) were evaluated. Results: The hSMSCs showed plate-adherence, fibroblast-like growth, expression of the stem-cell transcription factors Oct 4 and Nanog, and positive staining for mesenchymal stem cell (MSC) marker proteins (CD29, CD44, CD90, CD105, and vimentin) and a neural precursor marker (nestin). Moreover, the hSMSCs in this study were successfully differentiated into multiple mesenchymal lineages, including osteocytes, adipocytes, and chondrocytes. Neuron-like cell morphology and various neural markers were highly visible six hours after the neuronal induction of hSMSCs, but their neuron-like characteristics disappeared over time (24-48 hrs). Interestingly, when the chemical induction medium was changed to Dulbecco's Modified Eagle Medium (DMEM) supplemented with fetal bovine serum (FBS), the differentiated cells returned to their hSMSC morphology, and their cell number increased. These results indicate that chemically induced neuron-like cells should not be considered true nerve cells. Conclusion: Isolated hSMSCs have MSC characteristics and express a neural precursor marker, suggesting that human skin is a source of stem cells. However, the in vitro chemical neuronal induction of hSMSC does not produce long-lasting nerve cells and more studies are required before their use in nerve-tissue transplants.

• Bulletin of the Korean Chemical Society
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• 제33권6호
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• pp.1983-1988
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• 2012

Stem cell transplantation is emerging as a possible new treatment for liver cirrhosis, and recent animal studies have documented the benefits of stem cell therapy in a hepatic fibrosis model. However, the underlying mechanism of stem cell therapy is still unclear. Among the proposed mechanisms, the cell replacement mechanism is the oldest and most important, in which permanently damaged tissue can be replaced by normal tissue to restore function. In the present study, Cy5.5-labeled superparamagnetic iron oxide (SPIO) was used to label human mesenchymal stem cells. The uptake of fluorescently labeled nanoparticles enabled the detection and monitoring of the transplanted stem cells; therefore, we confirmed the direct incorporation and differentiation of SPIO into the hepatocyte-like transplanted stem cells by detecting human tyrosine aminotransferase (TAT), well-known enzymatic marker for hepatocyte-specific differentiation.

• 한국수정란이식학회:학술대회논문집
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• 한국수정란이식학회 2006년도 The 6th Intermational Symposium on Developmental Biotechnology
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• pp.76-77
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• 2006

• 대한생식의학회:학술대회논문집
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• 대한불임학회 2006년도 The 5th Biannual Meeting of Pacific Rim Society for Fertility and Sterility
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• pp.172.1-172.1
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• 2006