Wnt/β-catenin signaling in adult mammalian epithelial stem cells

- Wnt/β-catenin signaling is a critical regulator of adult stem cells in mammalian epithelia.
- The β-catenin target gene Lgr5 is a marker of adult stem cells in the intestine and skin.
- Purified Lgr5+ intestinal stem cells can be cultured using organoid technology.
- Aberrant Wnt/β-catenin signaling is found in colorectal carcinomas and different epidermal tumors.

Adult stem cells self-renew and replenish differentiated cells in various organs and tissues throughout a mammal's life. Over the last 25 years an ever-growing body of knowledge has unraveled the essential regulation of adult mammalian epithelia by the canonical Wnt signaling with its key intracellular effector β-catenin. In this review, we discuss the principles of the signaling pathway and its role in adult epithelial stem cells of the intestine and skin during homeostasis and tumorigenesis. We further highlight the research that led to the identification of new stem cell markers and methods to study adult stem cells ex vivo.