Jaejin Cho

Phenotypic characterization and in vivo localization of human adipose-derived mesenchymal stem cells.

Human adipose-derived mesenchymal stem cells (hADMSCs) are a potential cell source for autologous cell therapy due to their regenerative ability. However, detailed cytological or phenotypic characteristics of these cells are still unclear. Therefore, we determined and compared cell size, morphology, ultrastructure, and immunohistochemical (IHC) expression profiles of isolated hADMSCs and cells located in human adipose tissues. We also characterized the localization of these cells in vivo. Light microscopy examination at low power revealed that hADMSCs acquired a spindle-shaped morphology after four passages. Additionally, high power views showed that these cells had various sizes, nuclear contours, and cytoplasmic textures. To further evaluate cell morphology, transmission electron microscopy was performed. hADMSCs typically had ultrastructural characteristics similar to those of primitive mesenchymal cells including a relatively high nuclear/cytosol ratio, prominent nucleoli, immature cytoplasmic organelles, and numerous filipodia. Some cells contained various numbers of lamellar bodies and lipid droplets. IHC staining demonstrated that PDGFR and CD10 were constitutively expressed in most hADMSCs regardless of passage number but expression levels of α-SMA, CD68, Oct4 and c-kit varied. IHC staining of adipose tissue showed that cells with immunophenotypic characteristics identical to those of hADMSCs were located mainly in the perivascular adventitia not in smooth muscle area. In summary, hADMSCs were found to represent a heterogeneous cell population with primitive mesenchymal cells that were mainly found in the perivascular adventitia. Furthermore, the cell surface markers would be CD10/PDGFR. To obtain defined cell populations for therapeutic purposes, further studies will be required to establish more specific isolation methods.

Porcine PD-L1: cloning, characterization, and implications during xenotransplantation

Abstract: Background:  Effective intervention achieved by manipulating cell‐mediated xenogeneic immune responses would critically increase the clinical feasibility of xenotransplantation as immediate hyperacute rejections become controllable through genetic modulations of donor organs. Endogenous negative regulatory signals like the programmed death 1 (PD‐1)‐programmed death ligand 1 (PD‐L1) system are candidate targets for the control of cell‐mediated xenogeneic immune response.

Role of complement regulatory proteins in the survival of murine allo-transplanted Sertoli cells.

Sertoli cells (SC) are known to contain immunoprotective properties, which allow them to survive as allografts without the use of immunosuppressive drugs. Experiments were designed to determine which factors are related to prolonged survival of allogeneic SC. Balb/c derived Sertoli (TM4) and colon cancer (CT-26) cell lines were implanted beneath the kidney capsule of non-immunosuppressed C57BL/6 mice and compared their survival as allografts. Compared to TM4 graft, which survived more than 7 days after transplantation, CT-26 showed massive infiltration of polymorphonuclear cells, necrosis and enlargement of draining lymph nodes. Cultured cell lines showed no differences in their expression patterns of FasL, TGF β1, clusterin and two complement regulatory proteins (CRP, i.e., membrane cofactor protein, MCP; decay accelerating factor, DAF), but protectin (CD59), another member of CRP was expressed only on TM4. These results suggest that CD59 and unknown factors may contribute to the prolonged survival of SC in non-immunoprivileged sites.

A potent small-molecule inducer of chondrogenic differentiation of human bone marrow-derived mesenchymal stem cells

We discovered a novel small-molecule modulator 5{i,2} that can specifically induce the chondrogenic differentiation of human bone marrow-derived mesenchymal stem cells (hBM-MSCs). Based on our biochemical and histological studies, 5{i,2} showed more of a directed differentiation of MSCs to chondrocyte balls compared to TGF-β3.

Direct Effect of Chenodeoxycholic Acid on Differentiation of Mouse Embryonic Stem Cells Cultured under Feeder-Free Culture Conditions

Chenodeoxycholic acid (CDCA), a farnesoid X receptor (FXR) ligand, is a member of the nuclear receptor family and is probably involved in regulating the cellular activities of embryonic stem (ES) cells. Recently, although it was reported that the FXR ligand can mediate differentiation, apoptosis, and/or growth arrest in several cell types, it is still not well known how CDCA mediates effects in ES cells. Therefore, we investigated the direct effect of CDCA on mES cells. Feeder-free mES cells were treated in a dose-dependent manner with CDCA (50, 100, and 200 μM) for 72 h, and then a 100 μM CDCA treatment was performed for an additional 72 h. We analyzed the morphology, cell growth, cell characteristics, immunocytochemistry, and RT-PCR. In CDCA-treated cells, we observed the disappearance of pluripotent stem cell markers including alkaline phosphatase, Oct4, and Nanog and a time- and dose-dependent increase in expression of nestin, PAX6, and α-smooth muscle actin, but not α-fetoprotein. The 100 μM CDCA-treated cells in their second passage continued this differentiation pattern similar to those in the controls. In conclusion, these results suggest that CDCA can guide mES cells by an FXR-independent pathway to differentiate into ectoderm and/or mesoderm, but not endoderm.

Age-dependent expression of immune-privilege and proliferation-related molecules on porcine Sertoli cells.

Abstract: Background: The immunoprotective nature of the testes has prompted numerous investigations into their supportive roles during allogeneic or xenogeneic cellular grafts. However, the optimal developmental stage of these cells in terms of maximum efficacy for cellular grafts has not been elucidated. In this study, the time‐dependent expressions of immune‐privilege‐ and proliferation‐related molecules in Sertoli cells were determined.

Both CD45RA+ and CD45RO+ human CD4+ T cells drive direct xenogeneic T-cell responses against porcine aortic endothelial cells.

Kim CH, Oh K, Kim D‐E, Lee SB, Yang JH, Lee G, Cho J, Lee D‐S. Both CD45RA+ and CD45RO+ human CD4+ T cells drive direct xenogeneic T‐cell responses against porcine aortic endothelial cells. Xenotransplantation 2010; 17: 224–232.

Establishment and characterization of porcine Sertoli cell line for the study of xenotransplantation.

Abstract:  Background:  An understanding of the main mechanism that determines the ability of immune privilege related to Sertoli cells (SC) will provide clues for promoting a local tolerogenic environment. In this report, we established neonatal porcine SC line and evaluated their characteristics.

Chondrogenesis of human umbilical cord-derived mesenchymal stem cells in vitro by TGFβ3 and BMP6

Human umbilical cord is easy to obtain because it is discarded after birth, so it can avoid the ethical issues. Chondrogenesis studies using MSCs from bone marrow, cord blood, adipose has been indicated that TGFβ3 and BMP6 stimulate chondrogenesis. Therefore, we investigated chondrogenesis of the hUC-MSCs on TGFβ3, BMP6 and combination of the two growth factors. We initiated chondrogenesis of the cells by giving physical forces to form 3D cell clusters. After the initiation, we gave four experimental groups for differentiation of the cells as follows; control, 10 ng/mL TGFβ3, 100 ng/mL BMP6, and the combination of 5 ng/mL TGFβ3 and 50 ng/mL BMP6. To analyze of the chondrogenesis, GAG contents, mRNA expression, histological and immunohistochemistry (IHC) were performed. To analyze GAG contents, GAG assay was measured and RT-PCR was performed to determine the chondrogenic markers. Histological analysis was performed through safranin O, alcian blue, and IHC was performed using collagen type I and II. GAG contents were increased that 184% by TGFβ3, 147% by BMP6 and 189% by the combination of TGFβ3 and BMP6 compared to control. The growth factors improved collagen II and aggrecan expression, especially, TGFβ3 and BMP6 were shown synergistic effect compared to only TGFβ3 or BMP6 treated. The histological and IHC analysis indicated that the chondrogenic differentiation in the TGFβ3 and the combination of TGFβ3 and BMP6 showed more cartilage deposition. In conclusion, TGFβ3 and BMP6 differentiated hUC-MSCs into chondrogenic clusters of the combination treatment of the two growth factors showed more efficient chondrogenic ability.