Regulation of intestinal stem cells.

Stem cells are essential for maintaining the tissue integrity of all adult tissues. The manipulation of adult stem cells has the potential for cell regeneration and in curing diseases; however, the intestinal stem cell remains enigmatic. Although much work has focused on characterization of the intestinal stem cell within its in vivo niche, the lack of reliable markers complicates its isolation and therefore its in vitro manipulation. Understanding what regulates the intestinal stem cell within its niche will provide valuable insight into how these cells can be manipulated in culture. Comparing the regulation of this niche in the developing and mature intestine is a valuable untapped resource. A small number of signaling pathways are functionally conserved during development. These pathways are beginning to emerge as critical regulators of the stem cell niche. This review focuses on the regulation of the intestinal stem cell niche.