FGF4-dependent stem cells derived from rat blastocysts differentiate along the trophoblast lineage

Abstract

Differentiated trophoblast cell lineages arise from trophoblast stem (TS) cells. To date such a stem cell population has only been established in the mouse. The objective of this investigation was to establish TS cell populations from rat blastocysts. Blastocysts were cultured individually on a feeder layer of rat embryonic fibroblasts (REFs) in fibroblast growth factor-4 (FGF4) and heparin supplemented culture medium. Once cell colonies were established REF feeder layers could be replaced with REF conditioned medium. The blastocyst-derived cell lines, in either proliferative or differentiated states, did not express genes indicative of ICM-derived tissues. In the proliferative state the cells expressed established stem cell-associated markers of TS cells. Cells ceased proliferation and differentiated when FGF4, heparin, and REF conditioned medium were removed. Differentiation was characterized by a decline of stem cell-associated marker gene expression, the appearance of large polyploid cells (trophoblast giant cells), and the expression of trophoblast differentiation-associated genes. Collectively, the data indicate that the rat blastocyst-derived cell lines possess many features characteristic of mouse TS cells but also possess some distinct properties. These rat TS cell lines represent valuable new in vitro models for analyses of mechanisms controlling TS cell renewal and differentiation.

Natural killer cells direct hemochorial placentation by regulating hypoxia-inducible factor dependent trophoblast lineage decisions

“…We next determined whether the impact of hypoxia on the development of junctional zone-specific trophoblast cell lineages was a direct action on the TS cell population and whether the response was dependent on HIF1B signaling. For these experiments, we used TS cells derived from rat blastocysts (28). We first evaluated the effects of a range of oxygen concentrations (0.5-2%) on Tpbpa gene expression by TS cells maintained in the stem cell state.…”

“…Blastocyst-derived rat TS cells were used to evaluate the effects of low oxygen on trophoblast lineage decisions (28). TS cells maintained in the stem cell state were exposed to low oxygen using a NAPCO Series 8000WJ incubator (Thermo Scientific).…”

Trophoblast development

“…Derivation of TS cells from nuclear transfer-generated embryos has led to TS lines requiring lower levels of FGF4 and ACTIVIN for their survival, suggesting that such signalling can be altered (Rielland et al 2009). Recently, FGF-dependent rat TS cells, showing highly similar expression profiles to mouse TS cells, have been derived from blastocyst outgrowths (Asanoma et al 2011). However, TS lines that are independent of FGF signalling have also been established in rats as well as in another rodent, the common vole (Grigor'eva et al 2009, Chuykin et al 2010.…”

NK cells, hypoxia and trophoblast cell differentiation

“…14,22 TS cell populations are an excellent in vitro model system for elucidating mechanisms regulating differentiation. 23,24 TS cell exposure to a range of oxygen tensions can differentially influence cell proliferation and differentiation. 14,[25][26][27] The impact of oxygen tension on development of invasive trophoblast lineages from TS cell populations has received little attention.…”