Establishment and characterization of Bovine trophoblast stem cells (bTSCs) growing as adherent cells or vesicles

Understanding embryonic development still remains one of the main challenge in developmental biology. Using 3D in vitro models of early embryonic development in the mouse and human, scientists hope to decipher embryonic mechanisms, in particular the initial arrangement and interaction of cells within the embryonic structure. To date, there are very few models established for livestock species. In this study, we have derived and characterized bovine trophoblastic stem cells (bTSCs) that we further used to establish with bESCs (bovine embryonic stem cells) the first in vitro model of bovine blastoïds. The bTSCs were esablished using IVF embryos grown on inactivated BEF (bovine embryonic fibroblasts) in 2iTS medium composed of DMEM/F12 as a basis supplemented with Neurobasal, supplements WNT3A and small molecules as inhibitors of signaling pathways. Once established, the 2iTS cells were routinely passaged every 3-4 days for adherent ones with a splitting ratio of around 1/6 and by dilution of 1/6 for the cells in suspension.