Trophoblast stem cell derivation, cross-species comparison and use of nuclear transfer: New tools to study trophoblast growth and differentiation

Abstract

The trophoblast is a supportive tissue in mammals that plays key roles in embryonic patterning, foetal growth and nutrition. It shows an extensive growth up to the formation of the placenta. This growth is believed to be fed by trophoblast stem cells able to self-renew and to give rise to the differentiated derivatives present in the placenta. In this review, we summarize recent data on the molecular regulation of the trophoblast in vivo and in vitro. Most data have been obtained in the mouse, however, whenever relevant, we compare this model to other mammals. In ungulates, the growth of the trophoblast displays some striking features that make these species interesting alternative models for the study of trophoblast development. After the transfer of somatic nuclei into oocytes, studies in the mouse and the cow have both underlined that the trophoblast may be a direct target of reprogramming defects and that its growth seems specifically affected. We propose that the study of TS cells derived from nuclear transfer embryos may help to unravel some of the epigenetic abnormalities which occur therein.

A small set of extra-embryonic genes defines a new landmark for bovine embryo staging

“…Last but not least, knowing that species-specific mechanisms do exist, anatomical equivalents are difficult to define and gene regulation is difficult to transpose (Degrelle et al 2005, Rielland et al 2008, it is hard to give an answer on the universal value of gene expression patterns in the absence of an evo-devo approach including out-groups, as illustrated recently (Coolen et al 2009). Figure 6 These predictive genes are in silico connected to the patterning genes.…”

Trophoblast Stem Cells: Models for Investigating Trophectoderm Differentiation and Placental Development

“…Upon aggregation with mouse embryos, they can give rise to all trophoblast elements of the definitive mouse placenta (9), but they do not contribute to the embryonic germ layers giving rise to the tissues of the fetus proper. TSC derived directly from trophectoderm offer an appealing system with which to investigate the regulation of trophoblast differentiation because they putatively represent the earliest trophoblast progenitor population (10).…”

“…The ethical considerations and/or expense of conducting studies on periimplantation embryos and very early pregnancy implantation sites limit the studies that can be performed in vivo to elucidate trophoblast function and mechanisms of differentiation. Such in vivo studies in the murine model have provided the basis for validating TSC lines with specific gene expression profiles (10), but without similar guidance in primates the assumption cannot be made that in vitro-derived TSC function in an identical manner to their in vivo counterparts. The rhesus monkey…”

SATB Homeobox Proteins Regulate Trophoblast Stem Cell Renewal and Differentiation

“…TS cells are the antecedents of all trophoblast lineages that comprise the mature placenta (8,9). Culture conditions have been established that promote TS cell stemness or facilitate differentiation (6,10).…”