For want of a colonic stem cell niche, colonic stem cells are lost. For want of colonic stem cells, colonic epithelial integrity is lost. For want of colonic epithelial integrity, life is lost. So, the message is clear. Maintain a healthy colonic stem cell niche or suffer grave consequences.

Although the colonic stem cell is of unquestionable importance, it remains something of a mystery, one that has attracted the attention of scientists based at the University of Zurich. These scientists, led by Konrad Basler, Ph.D., have just uncovered a big clue. They have discovered the cells that form the stem cell niche.

These cells, the scientists recently reported, are subepithelial mesenchymal GLI1-expressing cells. These cells surround epithelial crypts, or small molds in the epithelium, which contain stem cells that rely on an activation signal called Wnt. According to Basler and his colleagues, the GLI1-expressing cells secrete Wnt, …