S. Vassilieva et al., Establishment of SSEA-1-and Oct-4-expressing rat embryonic stem-like cell lines and effects of cytokines of the IL-6 family on clonal growth, EXP CELL RE, 258(2), 2000, pp. 361-373
Here, we demonstrate long-term cultivation of alkaline phosphatase-positive
rat embryonic stem-like (RES) cell lines. RES cells were characterized by
their typical growth in highly compacted cell clusters, which were found to
be sensitive against enzymatic dissociation. RES cells expressed stage-spe
cific embryonic antigen-1 (SSEA-1) and transcription factor Oct-4, but Oct-
4 mRNA was detected at lower levels compared to mouse ES cells. Once establ
ished to tissue culture, RES cells were able to grow in the absence of feed
er cells under clonal conditions. Cytokines: of the interleukin-g family kn
own to maintain the undifferentiated state of mouse ES cells were comparati
vely analyzed for their capacity to maintain the undifferentiated growth of
two cell lines, RES-1 and RES-15, in a clonal assay. Rat ciliary neurotrop
hic factor (rCNTF), human oncostatin M (hOSM), and interleukin-6 and solubl
e interleukin-6 receptor (IL-6/sIL-6R) were found to support clonal growth
of RES cells, but the cytokines did not reach the efficiency of the colony
forming ability of leukemia inhibitory factor (LIF). When RES-1 and RES-15
cells were cultivated without feeder cells, SSEA-1 expression was maintaine
d after clonal growth in the presence of LIF and LIF + rCNTF, respectively.
Oct-4 mRNA was significantly detected in RES-15 cells when cultivated in t
he absence of feeder cells in media substituted by LIF and/or IL-6/sIL-6R,
as well as without cytokines. In summary, rat embryonic stem-like cell line
s could be established from rat blastocysts and were able to proliferate as
undifferentiated alkaline phosphatase-positive cells. Embryonal stem cell
properties, such as SSEA-1 and Oct-4 expression, were maintained by members
of the IL-6 family of cytokines, but most significantly by LIF. (C) 2000 A
cademic Press.