in vitro model for hepatocyte-like cell differentiation from Wharton's jelly derived-mesenchymal stem cells by cell-base aggregates

ABSTRACT

The present study investigated the differentiation potential of human Umbilical Cord Mesenchymal Stem Cells [UCMSCs] into hepatic lineage through embryonic body-like aggregate formation in the presence of IGF-1. Cells derived from Wharton's jelly have been reported to display a wide multilineage differentiation potential, showing some similarities to both embryonic [ESC] and mesenchymal stem cells [MSCs]. Human MSCs isolated from the umbilical cord were plated in 20 microL micro drops. A two-step differentiation protocol was used and the cell aggregates were exposed to the media supplemented with IGF, HGF, oncostatin M, and dexamethasone for 21 days. Immunoperoxidase and immuno-fluorescence were performed for cyrokeratins 18, 19 and albumin. Functional assays were done by periodic acid Schiff [PAS] and indocyanine green. The expression of cytokeratin 19 was shown to be higher in the cells derived from 3D spheroids compared to those cultured in conventional protocol. They showed a polygonal shape after being exposed to hepatogenic media. Immunostaining demonstrated the expression of cytokeratin-18, 19 and albumin by the differentiated cells. Besides, PAS staining revealed glycogen storage in differentiated cells. Also, a greater number of large size differentiated cells were found at the periphery of the expanded cell aggregates. We established a protocol for UCMSC differentiation into hepatocytes and these cells were morphologically and functionally similar to hepatocytes. Thus, hepatocyte differentiation may be facilitated by the UCMSCs aggregate formation before administration of the differentiation protocols