• The Korean Journal of Physiology and Pharmacology
• /
• 제16권5호
• /
• pp.349-353
• /
• 2012

Activated T cells express inhibitory receptors such as CTLA-4 that can downregulate immune responses. Blockade of or genetic deficiency in CTLA-4 can result in autoimmunity. Therefore, strategies to increase the inhibitory function of CTLA-4 may be attractive in settings of undesirable T cell responses such as autoimmunity or transplant rejection. We have tested the hypothesis that transgenic constitutive expression of CTLA-4 can further attenuate immune responses when compared with normal inducible expression. Our results indicate that transgenic expression of CTLA-4 in mouse T cells (CTLA-4-Tg T cells) results in reduced cell cycle progression and increased apoptosis of TCR-stimulated T cells. CTLA-4-Tg T cells display reduced T cell proliferation in an in vivo model of graft versus host disease (GVHD). These results further our understanding of how CTLA-4 can be manipulated to inhibit immune responses and may help development of new therapeutic strategies for clinical settings of autoimmunity and transplantation.

• Toxicological Research
• /
• 제32권3호
• /
• pp.251-258
• /
• 2016

Mesenchymal stem cells (MSCs) have been identified in multiple types of tissue and exhibit characteristic self-renewal and multi-lineage differentiation abilities. However, the possibility of oncogenic transformation after transplantation is concerning. In this study, we investigated the tumorigenic potential of umbilical cord blood-derived MSCs (hUCB-MSCs) relative to MRC-5 and HeLa cells (negative and positive controls, respectively) both in vitro and in vivo. To evaluate tumorigenicity in vitro, anchorage-independent growth was assessed using the soft agar colony formation assay. hUCB-MSCs and MRC-5 cells formed few colonies, while HeLa cells formed a greater number of larger colonies, indicating that hUCB-MSCs and MRC-5 cells do not have anchorage-independent proliferation potential. To detect tumorigenicity in vivo, hUCB-MSCs were implanted as a single subcutaneous injection into BALB/c-nu mice. No tumor formation was observed in mice transplanted with hUCB-MSCs or MRC-5 cells based on macro- and microscopic examinations; however, all mice transplanted with HeLa cells developed tumors that stained positive for a human gene according to immunohistochemical analysis. In conclusion, hUCB-MSCs do not exhibit tumorigenic potential based on in vitro and in vivo assays under our experimental conditions, providing further evidence of their safety for clinical applications.

• 대한의생명과학회지
• /
• 제23권3호
• /
• pp.238-250
• /
• 2017

Patient's primary tumor-derived tumor cell lines likely represent ideal tools for human tumor biology in vitro and in vivo. Here, we describe eight human gastric carcinoma cell lines derived from established tumors in vivo upon subcutaneous transplantation of primary gastric carcinoma specimens in BALB/c nude mice. These xenografted gastric tumor cell lines (GTX) displayed close similarity with primary gastric tumor tissues in their in vivo growth pattern and genomic alterations. GTX-085 cells were resistant to cisplatin, while GTX-087 was the most sensitive cell line. GTX-085 was the only cell line showing a metastatic potential. Epithelial cell adhesion molecule (EPCAM) expression was especially strong in all tissue samples, as well as in cell cultures. GTX-139, the largest tumor graft obtained after injection, displayed distinct expression of CD44v6, fibroblast growth factor receptor 2 (FGFR2), and prominin 1 (PROM1, also known as CD133). In summary, we established eight xenograft gastric cancer cell lines from gastric cancer patient tissues, with their histological and molecular features consistent with those of the primary tumors. The established GTX cell lines will enable future studies of their responses to various treatments for gastric cancer.

• Molecules and Cells
• /
• 제39권11호
• /
• pp.790-796
• /
• 2016

Dental pulp is a highly vascularized tissue requiring adequate blood supply for successful regeneration. In this study, we investigated the functional role of stem cells from human exfoliated deciduous teeth (SHEDs) as a perivascular source for in vivo formation of vessel-like structures. Primarily isolated SHEDs showed mesenchymal stem cell (MSC)-like characteristics including the expression of surface antigens and in vitro osteogenic and adipogenic differentiation potentials. Moreover, SHEDs were positive for NG2, ${\alpha}$-smooth muscle actin (SMA), platelet-derived growth factor receptor beta ($PDGFR{\beta}$), and CD146 as pericyte markers. To prove feasibility of SHEDs as perivascular source, SHEDs were transplanted into immunodeficient mouse using Matrigel with or without human umbilical vein endothelial cells (HUVECs). Transplantation of SHEDs alone or HUVECs alone resulted in no formation of vessel-like structures with enough red blood cells. However, when SHEDs and HUVECs were transplanted together, extensive vessel-like structures were formed. The presence of murine erythrocytes within lumens suggested the formation of anastomoses between newly formed vessel-like structures in Matrigel plug and the host circulatory system. To understand underlying mechanisms of in vivo angiogenesis, the expression of angiogenic cytokine and chemokine, their receptors, and MMPs was compared between SHEDs and HUVECs. SHEDs showed higher expression of1VEGF, SDF-$1{\alpha}$, and $PDGFR{\beta}$ than HUVECs. On the contrary, HUVECs showed higher expression of VEGF receptors, CXCR4, and PDGF-BB than SHEDs. This differential expression pattern suggested reciprocal interactions between SHEDs and HUVECs and their involvement during in vivo angiogenesis. In conclusion, SHEDs could be a feasible source of perivascular cells for in vivo angiogenesis.

• IMMUNE NETWORK
• /
• 제8권4호
• /
• pp.107-123
• /
• 2008

It has now been well documented in a variety of models that T regulatory T cells (Treg cells) play a pivotal role in the maintenance of self-tolerance, T cell homeostasis, tumor, allergy, autoimmunity, allograft transplantation and control of microbial infection. Recently, Treg cell are isolated and can be expanded in vitro and in vivo, and their role is the subject of intensive investigation, particularly on the possible Treg cell therapy for various immune-mediated diseases. A growing body of evidence has demonstrated that Treg cells can prevent or even cure a wide range of diseases, including tumor, allergic and autoimmune diseases, transplant rejection, graft-versus-host disease. Currently, a large body of data in the literature has been emerging and provided evidence that clear understanding of Treg cell work will present definite opportunities for successful Treg cell immunotherapy for the treatment of a broad spectrum of diseases. In this Review, I briefly discuss the biology of Treg cells, and summarize efforts to exploit Treg cell therapy for autoimmune diseases. This article also explores recent observations on pharmaceutical agents that abrogate or enhance the function of Treg cells for manipulation of Treg cells for therapeutic purpose.

• Molecules and Cells
• /
• 제45권2호
• /
• pp.53-64
• /
• 2022

Three-dimensional cultures of human neural tissue/organlike structures in vitro can be achieved by mimicking the developmental processes occurring in vivo. Rapid progress in the field of neural organoids has fueled the hope (and hype) for improved understanding of brain development and functions, modeling of neural diseases, discovery of new drugs, and supply of surrogate sources of transplantation. In this short review, we summarize the state-of-the-art applications of this fascinating tool in various research fields and discuss the reality of the technique hoping that the current limitations will soon be overcome by the efforts of ingenious researchers.

• Molecules and Cells
• /
• 제19권3호
• /
• pp.402-407
• /
• 2005

Bone marrow mesenchymal stem cells (MSCs) have shown potential for cardiac repair following myocardial injury, but this approach is limited by their poor viability after transplantation. To reduce cell loss after transplantation, we introduced the fibroblast growth factor-2 (FGF-2) gene ex vivo before transplantation. The isolated MSCs produced colonies with a fibroblast-like morphology in 2 weeks; over 95% expressed CD71, and 28% expressed the cardiomyocyte-specific transcription factor, Nkx2.5, as well as ${\alpha}$-skeletal actin, Nkx2.5, and GATA4. In hypoxic culture, the FGF-2-transfected MSCs (FGF-2-MSCs) secreted increased levels of FGF-2 and displayed a threefold increase in viability, as well as increased expression of the anti-apoptotic gene, Bcl2, and reduced DNA laddering. They had functional adrenergic receptors, like cardiomyocytes, and exposure to norepinephrine led to phosphorylation of ERK1/2. Viable cells persisted 4 weeks after implantation of $5.0{\times}10^5$ FGF-2-MSCs into infarcted myocardia. Expression of cardiac troponin T (CTn T) and a voltage-gated $Ca^{2+}$ channel (CaV2.1) increased, and new blood vessels formed. These data suggest that genetic modification of MSCs before transplantation could be useful for treating myocardial infarction and end-stage cardiac failure.

• International Journal of Stem Cells
• /
• 제16권3호
• /
• pp.251-259
• /
• 2023

Mesenchymal stromal cells (MSCs) have attracted scientific and medical interest due to their self-renewing properties, pluripotency, and paracrine function. However, one of the main limitations to the clinical application of MSCs is their loss of efficacy after transplantation in vivo. Various bioengineering technologies to provide stem cell niche-like conditions have the potential to overcome this limitation. Here, focusing on the stem cell niche microenvironment, studies to maximize the immunomodulatory potential of MSCs by controlling biomechanical stimuli, including shear stress, hydrostatic pressure, stretch, and biophysical cues, such as extracellular matrix mimetic substrates, are discussed. The application of biomechanical forces or biophysical cues to the stem cell microenvironment will be beneficial for enhancing the immunomodulatory function of MSCs during cultivation and overcoming the current limitations of MSC therapy.

• 한국생물공학회:학술대회논문집
• /
• 한국생물공학회 2001년도 추계학술발표대회
• /
• pp.475-478
• /
• 2001

체외에서 hematopoietic cells의 배양은 필수이식으로 하여금 hematopoietic malignancies로 인해 고통받는 환자들을 치료할 수 있다. 본 실험에서는 골수의 초기 농도$1.5{\times}10^6cells/ml$로 하여 IL-3(5ng/ml), SCF(5ng/ml)과 FL(25ng/ml)의 성장 인자들을 첨가함으로써 bone marrow의 전체 cell의 증식은 생성시키지 못 했지만 LTC-IC는 3.6배의 증식을 가져왔다.

• Journal of Chest Surgery
• /
• 제45권5호
• /
• pp.287-294
• /
• 2012

Background: Biologic valved grafts are important in cardiac surgery, and although several types of graft are currently available, most commercial xenografts tend to cause early disfiguration due to intimal proliferation and calcification. We studied the graft failure patterns on non-fixed and glutaraldehyde-fixed pulmonary xenograft in vivo animal experiment. Materials and Methods: Pulmonary valved conduits were obtained from the right ventricular outflow tract of eleven miniature pigs. The grafts were subjected to 2 different preservation methods; with or without glutaraldehyde fixation: glutaraldehyde fixation (n=7) and non-glutaraldehyde fixation (n=4). The processed explanted pulmonary valved grafts of miniature pig were then transplanted into eleven goats. Calcium quantization was achieved in all of the explanted xenograft, hemodynamic, histopathologic and radiologic evaluations were performed in the graft which the transplantation period was over 300 days (n=7). Results: Grafts treated with glutaraldehyde fixation had more calcification and conduit obstruction in mid-term period. Calcium deposition also appeared much higher in the glutaraldehyde treated graft compared to the non-glutaraldehyde treated graft (p<0.05). Conclusion: The present study suggests that xenografts prepared using glutaraldehyde fixation alone appeared to have severe calcification compared to the findings of non-glutaraldehyde treated xenografts and to be managed with proper anticalcification treatment and novel preservation methods. This experiment gives the useful basic chemical, histologic data of xenograft failure model with calcification for further animal study.