Wnt signaling in stem cells during development and cell lineage specification.

During embryo development, cell proliferation, cell fate specification and tissue patterning are coordinated and tightly regulated by a handful of evolutionarily conserved signaling pathways activated by secreted growth factor families including fibroblast growth factor (FGF), Nodal/bone morphogenetic protein (BMP), Hedgehog and Wnt. The spatial and temporal activation of these signaling pathways elicit context-specific cellular responses that ultimately shape the different tissues of the embryo. Extensive efforts have been dedicated to identifying the molecular mechanisms underlying these signaling pathways during embryo development, adult tissue homeostasis and regeneration. In this review, we first describe the role of the Wnt/β-catenin signaling pathway during early embryo development, axis specification and cell differentiation as a prelude to highlight how this knowledge is being leveraged to manipulate Wnt/β-catenin signaling activity with small molecules and biologics for the directed differentiation of pluripotent stem cells into various cell lineages that are physiologically relevant for stem cell therapy and regenerative medicine.