Wharton's jelly derived from mesoderm of umbilical cord matrix is an abundant source of stem cells such as mesenchymal and more primitive stem cells that don't raise the ethical issues associated with embryonic stem cells. The Oct-4 POU transcription factor, Nanog, and Sox-2 are expressed in embryonic stem cells and have been implicated in embryonic development and maintenance of pluripotency. The present study examined the expression of early transcription factors, Oct-4, Nanog, and Sox-2, and capability of differentiation to osteocytes, adipocytes, and chondrocytes of the cells of Wharton's jelly isolated from porcine umbilical cord. Wharton's jelly was obtained from the umbilical cord of post-natal piglets (immediately after birth). This tissue was diced into 2-mm-diameter explants and attached to tissue culture dishes. Cells were then cultured in DMEM/F12 supplemented with 10% fetal blood serum (FBS), 10 ng mL–1 basic fibroblast growth factor (bFGF), 1 nm dexamethasone, and 10 nm insulin at 38.5�C, 5% CO2 in air. Expression of Oct-4, Nanog, and Sox-2 by these cells was analyzed by immunocytochemistry and RT-polymerase chain reaction (PCR), and compared with expression by porcine bone marrow MSCs established in our laboratory. Osteogenic, adipogenic, and chondrogenic differentiation were induced following the protocols described earlier (Jin et al. 2007 Int. J. Dev. Biol. 51, 85–90; Mohana Kumar et al. 2007 Mol. Cells, in press). Cells isolated from Wharton's jelly expressed Oct-4, Nanog, and Sox-2 especially in colonies/clusters, as observed by immunocytochemistry and gene expression by RT-PCR, and this expression was higher than by MSCs isolated from bone marrow. Osteocytes were documented by the formation of the mineral nodules with alkaline phosphatase-positive cells and deposition of calcium. Differentiation into adipocytes was exhibited by oil red O staining of lipid vacuoles. Alcian blue staining for proteoglycans demonstrated the differentiation of chondrogenic cells. In conclusion, the results of the present study suggest that cells isolated from Wharton's jelly have properties of primitive pluripotency and multilineage differentiation. These stem cells, therefore, can serve as an easily accessible and expandable source possessing potential for preclinical applications using a large animal model.
This work was supported by Grant No. 20070301034040 from Bio-organ, Republic of Korea.
Embryonic stem cells conditioned medium enhances Wharton’s jelly-derived mesenchymal stem cells expansion under hypoxic condition
