• Experimental and Molecular Medicine
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• v.50 no.11
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• pp.1.1-1.10
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• 2018

Bone marrow-derived mesenchymal stem cells (BMMSCs) are used extensively for cardiac repair and interact with immune cells in the damaged heart. Macrophages are known to be modulated by stem cells, and we hypothesized that priming macrophages with BMMSCs would enhance their therapeutic efficacy. Rat bone marrow-derived macrophages (BMDMs) were stimulated by lipopolysaccharide (LPS) with or without coculture with rat BMCs. In the LPS-stimulated BMDMs, induction of the inflammatory marker iNOS was attenuated, and the anti-inflammatory marker Arg1 was markedly upregulated by coculture with BMMSCs. Myocardial infarction (MI) was induced in rats. One group was injected with BMMSCs, and a second group was injected with MIX (a mixture of BMMSCs and BMDMs after coculture). The reduction in cardiac fibrosis was greater in the MIX group than in the BMC group. Cardiac function was improved in the BMMSC group and was substantially improved in the MIX group. Angiogenesis was better in the MIX group, and anti-inflammatory macrophages were more abundant in the MIX group than in the BMMSC group. In the BMMSCs, interferon regulatory factor 5 (IRF5) was exclusively induced by coculture with macrophages. IRF5 knockdown in BMMSCs failed to suppress inflammatory marker induction in the macrophages. In this study, we demonstrated the successful application of BMDMs primed with BMMSCs as an adjuvant to cell therapy for cardiac repair.

• Molecules and Cells
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• v.37 no.10
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• pp.742-746
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• 2014

The epithelial cell adhesion molecule (EpCAM, also known as CD326) is a transmembrane glycoprotein that is specifically detected in most adenocarcinomas and cancer stem cells. In this study, we performed a Cell systematic evolution of ligands by exponential enrichment (SELEX) experiment to isolate the aptamers against EpCAM. After seven round of Cell SELEX, we identified several aptamer candidates. Among the selected aptamers, EP166 specifically binds to cells expressing EpCAM with an equilibrium dissociation constant (Kd) in a micromolar range. On the other hand, it did not bind to negative control cells. Moreover, EP166 binds to J1ES cells, a mouse embryonic stem cell line. Therefore, the isolated aptamers against EpCAM could be used as a stem cell marker or in other applications in both stem cell and cancer studies.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.37 no.2
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• pp.97-108
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• 2011

Cancer stem cells have stem cell-like features, such as the ability for self-renewal and differentiation but show unlimited growth because they have the lost normal regulation of cell growth. Cancer stem cells and normal stem cells have similar features. They show high motility, diversity of progeny, robust proliferative potential, association with blood vessels, immature expression profiles, nestin expression, epidermal growth factor (EGF)-receptor expression, phosphatase and tensin homolog (PTEN) expression, hedgehog pathway activity, telomerase activity, and Wnt pathway activity. On the other hand, with cancer cells, some of these signaling pathways are abnormally modified. In 1875, Cohnheim suggested the concept of cancer stem cells. Recently, evidence for the existence of cancer stem cells was identified. In 1994, the cancer stem cells' specific cell surface marker for leukemia was identified. Since then, other specific cell surface markers for cancer stem cells in solid tumors (e.g. breast and colon cancer) have been identified. In oral cancer, studies on cancer stem cells have been performed mainly with squamous cell carcinomas. Oral cancer specific cell surface markers, which are genes strongly expressed in oral cancer and cancer stem cell specific side populations, have been identified. Cancer stem cells are resistant to radiotherapy and chemotherapy. Therefore, to eliminate malignant tumors efficiently and reduce the recurrence rate, therapy targeting cancer stem cells needs to be performed. Currently, studies targeting the cancer stem cells' specific signaling pathways, telomerase and tumor vasculatures are being done.

• Proceedings of the KSAR Conference
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• 2001.03a
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• pp.38-38
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• 2001

Spermatogonial stem cells은 sperrnatogenesis에서 중요한 역할을 하며, 곡세정관의 기저막에 위치하고 있는 것으로 알려져 있다. 그러나, 그 동안 이 세포에 특이하게 발현되는 marker가 거의 알려져 있지 않아 spermatogonial stem cell의 연구에 많은 어려움을 가져왔다. 최근 일반적인 stem cell이 갖는 특성 중, 기저막과 상호작용을 하는 surface protein으로 integrin이 존재한다는 사실을 이용하여, anti-$\alpha$$_{6}$/ 또는 anti-$\beta$$_1$ integrin항체로 germ cell을 선발하여 정소에 이식한 결과, 높은 효율로 이식세포유래의 정자발생이 가능하다는 결과가 보고되었다 (Shinohara et al., 1999). 한편, 항암제의 일종인 busulfan을 마우스에 투여(40mg/kg)한 후 4-5주가 경과하면 세정관의 기저막에 위치하는 spermatogonia를 제외하고 대부분의 생식세포는 소멸한다 본 실험의 목적은 이러한 사실들을 이용하여 spermatogonial stem cell의 특성을 밝히고, 이 생식세포를 보다 간편하고 손쉽게 선발할 수 있는 시스템을 확립하는데 있다. Busulfan처리 후 5주가 경과된 마우스와 정상적인 13주령의 마우스 testis로부터 세포를 분리한 후 FITC-conjugated anti-IgG를 이용한 면역형광법으로 측정.분석한 결과, 형광표식된 세포비율이 대조군과 비교하여 busulfan을 처리한 경우에서 유의적인 증가를 보였다.(17$\pm$3.8%. 0.7$\pm$0.3% busulfan vs control). 또한, IgG와 결합한 단백질이 존재하는 이들 세포들은 곡세정관의 기저막을 따라 위치하며, 단백질과 복합체를 형성한 IgG는 anti-Ig $G_{2a}$와 반응하지 않는다는 사실을 관찰했다. 이러한 IgG 복합체를 형성한 세포들의 특성을 이용하여, IgG와 반응을 하지 않는 것으로 확인된 이차 항체인 an1i-Ig $G_{2}$와 일차 항체인 anti-$\alpha$$_{6}$ 또는 anti-$\beta$$_1$ integrin항체를 이용하여 측정.분석하였다. Busulfan을 처리한 마우스 정소에서 분리한 세포를 다시 laminin으로 코팅된 dish에서 선발.회수해서, anti-lgG, anti-$\alpha$$_{6}$ 또는 anti-$\beta$$_1$ integrin항체로 각각 표식된 세포비율을 비교하였다. Laminin으로부터 선발.회수한 세포에서는 IgG복합체가 $\alpha$$_{6}$ 또 는 $\beta$$_1$integrin과 거의 같은 수준에서 높은 비율로 표식되었다. 결론적으로, busulfan에 의해 유도된 IgG와 결합가능한 단백질은 $\alpha$$_{6}$나 $\beta$$_1$ integrin과 마찬가지로 immunoglobulin G를 이용하여 spermatogonial stem cell의 선발을 가능하게 했다. 따라서, busulfan처리시 IgG는 미분화된 정조세포의 선발을 위한 하나의 marker로서 사용가능함을 시사한다.다.

• Molecules and Cells
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• v.40 no.1
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• pp.54-65
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• 2017

Although cancer/testis antigen DDX53 confers anti-cancer drug-resistance, the effect of DDX53 on cancer stem cell-like properties and autophagy remains unknown. MDA-MB-231 ($CD133^+$) cells showed higher expression of DDX53, SOX-2, NANOG and MDR1 than MDA-MB-231 ($CD133^-$). DDX53 increased in vitro self-renewal activity of MCF-7 while decreasing expression of DDX53 by siRNA lowered in vitro self-renewal activity of MDA-MB-231. DDX53 showed an interaction with EGFR and binding to the promoter sequences of EGFR. DDX53 induced resistance to anti-cancer drugs in MCF-7 cells while decreased expression of DDX53 by siRNA increased the sensitivity of MDA-MB-231 to anti-cancer drugs. Negative regulators of DDX53, such as miR-200b and miR-217, increased the sensitivity of MDA-MB-231 to anti-cancer drugs. MDA-MB-231 showed higher expression of autophagy marker proteins such as ATG-5, $pBeclin1^{Ser15}$ and LC-3I/II compared with MCF-7. DDX53 regulated the expression of marker proteins of autophagy in MCF-7 and MDA-MB-231 cells. miR-200b and miR-217 negatively regulated the expression of autophagy marker proteins. Chromatin immunoprecipitation assays showed the direct regulation of ATG-5. The decreased expression of ATG-5 by siRNA increased the sensitivity to anti-cancer drugs in MDA-MB-231 cells. In conclusion, DDX53 promotes stem cell-like properties, autophagy, and confers resistance to anti-cancer drugs in breast cancer cells.

• Reproductive and Developmental Biology
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• v.28 no.1
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• pp.65-70
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• 2004

In mammals, male and female germline stem cells are derived from primodial germ cells. Despite many efforts to identify stem cells from gonads, there has been little successe to identify germline stem cells yet. In this study, we isolate and characterized porcine germline stem cells using only stem cell markers that are prevalently expressed in various tissues. Gonadal cells derived from both male and female formed colonies and showed AP activities and different lectin binding properties. Pluripotency of germline stem cells was also identified by positive signals against putative stem cells markers such as SSEA-1 and SSEA-3. In addition, nestin was also found in primary gonad cells that have a similar morphology to the AP-positive cells. The nestin expression suggests that the germline stem cells may have similar expression of the prevalent stem cell markers found in other tissues. The demonstration of nestin expression together with pluripotent cell markers calls further investigation of the possible differentiation of nestin-positive cells into neurons.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.31 no.1
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• pp.39-45
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• 2005

Stem cell therapy using mesenchymal stem cells(MSCs) transplantation have been paid attention because of their powerful proliferation and pluripotent differentiating ability. Although umbilical cord blood (UCB) is well known to be a rich source of hematopoietic stem cells with practical and ethical advantages, the presence of mesenchymal stem cells (MSCs) in UCB has been controversial and it remains to be validated. In this study, we examine the presence of MSCs in UCB harvests and the prevalence of them is compared to that of endothelial progenitor cells. For this, CD34+ and CD34- cells were isolated and cultured under the endothelial cell growth medium and mesenchymal stem cell growth medium respectively. The present study showed that ESC-like cells could be isolated and expanded from preterm UCBs but were not acquired efficiently from full-terms. They expressed CD14-, CD34-, CD45-, CD29+, CD44+, CD105+ cell surface marker and could differentiate into adipogenic and osteogenic lineages. Our results suggest that MSCs are fewer in full-term UCB compared to endothelial progenitor cells.

• Clinical and Experimental Reproductive Medicine
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• v.45 no.2
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• pp.75-81
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• 2018

Objective: Recapitulation of the spermatogenesis process in vitro is a tool for studying the biology of germ cells, and may lead to promising therapeutic strategies in the future. In this study, we attempted to transdifferentiate Wharton's jelly-derived mesenchymal stem cells (WJ-MSCs) into male germ cells using all-trans retinoic acid and Sertoli cell-conditioned medium. Methods: Human WJ-MSCs were propagated by the explant culture method, and cells at the second passage were induced with differentiation medium containing all-trans retinoic acid for 2 weeks. Putative germ cells were cultured with Sertoli cell-conditioned medium at $36^{\circ}C$ for 3 more weeks. Results: The gene expression profile was consistent with the stage-specific development of germ cells. The expression of Oct4 and Plzf (early germ cell markers) was diminished, while Stra8 (a premeiotic marker), Scp3 (a meiotic marker), and Acr and Prm1 (postmeiotic markers) were upregulated during the induction period. In morphological studies, approximately 5% of the cells were secondary spermatocytes that had completed two stages of acrosome formation (the Golgi phase and the cap phase). A few spermatid-like cells that had undergone the initial stage of tail formation were also noted. Conclusion: Human WJ-MSCs can be transdifferentiated into more advanced stages of germ cells by a simple two-step induction protocol using retinoic acid and Sertoli cell-conditioned medium.

• 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.

• Molecules and Cells
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• v.19 no.1
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• pp.31-38
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• 2005

Human embryonic stem (hES) cells have unique features including unlimited growth capacity, expression of specific markers, normal karyotypes and an ability to differentiate. Many investigators have tried to use hES cells for cell-based therapy, but there is little information about the properties of available hES cell lines. We compared the characteristics of three hES cell lines. The expression of SSEA-1, -3, -4, and APase, was examined by immunocytochemistry, and Oct-4 expression was analyzed by RT-PCR. Differentiation of the hES cells in vitro and in vivo led to the formation of embryoid bodies (EBs) or teratomas. We examined the expression of tissue-specific markers in the differentiated cells by semiquantitative RT-PCR, and the ability of each hES cell line to proliferate was measured by flow cytometry of DNA content and ELISA. The three hES cell lines were similar in morphology, marker expression, and teratoma formation. However there were significant differences (P < 0.05) between the differentiated cells formed by the different cell lines in levels of expression of tissue-specific markers such as renin, kallikrein, Glut-2, ${\beta}-$ and ${\delta}-globin$, albumin, and ${\alpha}1-antitrypsin$ (${\alpha}1-AT$). The hES cell lines also differed in proliferative activity. Our observations should be useful in basic and clinical hES cell research.