[CHARACTERISTICS OF NEW MESENCHYMAL STEM CELL LINE DERIVED FROM HUMAN EMBRYONIC STEM CELLS]

New nonimmortalized fibroblast-like cell line SC6-MSC has been obtained from a line of human embryonic stem cells (ESC)--SC6. Numerical and structural karyotypic analysis has shown hypodiploidy karyotypic: 45, X0 in this line. The average cell population doublings time, for SC6-MSC is 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 for 8-10 passages with a consequent gradual decrease of proliferative activity, which ended to 20th passage. To determine the line's status, the analysis of the surface markers by flow cytometry was carried out. We have revealed the expression of surface antigens CD44, CD73, CD90, CD105 and HLA-ABC characteristic for human MSC, and the absence of CD34 and HLA-DR expression. However, the level of expression of surface markers CD90 and CD105 was significantly lower in comparison with other MSC lines including the line SC5-MSC derived from the line human ESC-SC5. Immunofluorescence analysis of the expression of the surface markers and transcription factor Oct-4 characteristic for human embryonic stem cells showed the absence of Oct-4 expression and the presence of SSEA-4 and TRA-1-60 expression, which is characteristic for a number of MSC lines with normal karyotype. Immunofluorescence analysis has shown the presence of the markers of early differentiation in the derivates of three germ layers, characteristic for human ESC, which in corresponding microenvironments may allow MSC to be useful for reparation of tissue injures. The directed osteogenic and chondrogenic differentiation of line SC6-MSC has shown. However, no directed adipogenic differentiation of this line has been found. The obtained results with high probability may indicate what alteration of chromosomal and, accordingly, gene balance, in line SC6-MSC with karyotype 45, X0 resulted in decrease in differential potential, in expression CD90, associated in particular with the processes of differentiation and aging of cells.