Efficient Induction of Syncytiotrophoblast Layer II Cells from Trophoblast Stem Cells by Canonical Wnt Signaling Activation

Summary The syncytiotrophoblast layer is the most critical and prominent tissue in placenta. SynT cells are differentiated from trophoblast stem cells (TSCs) during early embryogenesis. Mouse TSCs can spontaneously differentiate into cells of mixed lineages in vitro upon withdrawal of stemness-maintaining factors. However, differentiation into defined placental cell lineages remains challenging. We report here that canonical Wnt signaling activation robustly induces expression of SynT-II lineage-specific genes Gcm1 and SynB and suppresses markers of other placental lineages. In contrast to mouse TSCs, the induced SynT-II cells are migratory. More importantly, the migration depends on hepatocyte growth factor (HGF) and the c-MET signaling axis. Furthermore, HGF-expressing cells lie adjacent to SynT-II cells in developing murine placenta, suggesting that HGF/c-MET signaling plays a critical role in SynT-II cell morphogenesis during the labyrinth branching process. The availability of SynT-II cells in vitro will facilitate molecular understanding of labyrinth layer development.
Highlights • Wnt is sufficient to induce SynT-II cells from trophoblast stem cells • Induced SynT-II cells are migratory and are independent on EMT • Hepatocyte growth factor/c-MET is essential for SynT-II cell migration
Zhu and colleagues successfully induce mouse syncytiotrophoblast (SynT) layer II cells from trophoblast stem cells by activation of canonical Wnt signaling. The induced SynT-II cells are migratory and are dependent on HGF/c-MET pathway. The availability of SynT-II cells in vitro should facilitate molecular study of labyrinth layer development in placenta.