Characterization of a novel mesenchymal stem cell line derived from human embryonic stem cells

Abstract

A novel nonimmortalized fibroblast-like cell line SC6-MSC was derived from SC6 human embryonic stem cells (ESCs). Numerical and structural karyotypic analyses of these cells have revealed that it is hypodiploid: 45, X0. SC6-MSC average population doubling time was 26.0 ± 0.4 h at the 8th passage and 82.0 ± 9.2 h at the 18th passage. The growth curves showed active proliferation during passages 8–10 and consequent gradual decrease of the proliferative activity that stopped by the 20th passage. Flow cytometry analysis of surface markers has been carried to determine the line status. Revealed positive expression of CD44, CD73, CD90, CD105, and HLA-ABC and lack of CD34 and HLA-DR surface antigens are common for mesenchymal stem cells (MSCs). However, expression of CD90 and CD105 surface markers was significantly lower than for other MSC lines, including the line SC5-MSC derived from human ESC line SC5. Immunofluorescence analysis of surface markers and Oct-4 transcription factor, characteristic for human embryonic stem cells, showed the lack of Oct-4 expression and the presence of SSEA-4 and TRA-1-60 typical for a number of karyotypically normal MSC lines. Immunofluorescence assay showed the presence of the early differentiation markers of three germ layer derivates common for human ESCs. This shows that MSCs may be useful for reparation of tissue damage in corresponding microenvironments. It was revealed that SC6-MSC cells were able to differentiate into osteogenic and chondrogenic, but not adipogenic, directions. The results obtained indicate with high probability that disordered chromosomal and, accordingly, gene balance, in SC6-MSC line with karyotype 45, X0 result in decreased differential potential and expression of CD90 associated with the processes of cell differentiation and aging.