Wnt Signaling in Adult Stem Cells: Tissue Homeostasis and Regeneration
This chapter discusses the role of (mostly canonical) Wnt signaling in adult stem cells, beginning with intestinal stem cells, as for this tissue most is known about the role of Wnt signaling in self-renewal, differentiation, and quiescence. Another tissue that displays rapid turnover, the skin, also contains stem cells that are dependent on Wnt signaling. Compared to the convincing studies on the role of Wnt signaling in adult stem cells in skin and gut, a role for Wnt in adult HSCs (the prototypical adult stem cell) has proven much more difficult to demonstrate. Although the strength of its signals in HSCs is possibly lower than in other adult stem cell systems, the Wnt pathway is likely to play an important role in the self-renewal program in hematopoiesis.