Notch Signaling in Mammalian Intestinal Stem Cells: Determining Cell Fate and Maintaining Homeostasis.

The intestine serves mainly as a place for digestion and absorption and functions as an immune and endocrine organ. Intestinal stem cells (ISCs) play critical roles in the maintenance of intestinal homeostasis and regeneration, and a complex of signaling pathways is involved in these processes. The Notch signaling pathway is induced via distinct cell-to-cell connections, which are activated through the binding of the Notch ligand on the surface of niche cells to the Notch receptor on ISCs. Numerous studies have shown the central importance of Notch signaling in the proliferation and differentiation of ISCs. Here, we summarize the latest research progress on the crucial functions of Notch signaling in maintaining homeostasis and determining the cell fate of ISCs. Furthermore, the challenges of Notch signaling in colon cancer therapy strategies are also discussed. Several important questions regarding Notch regulation of ISCs are proposed.