Intestinal epithelial stem cells that express Lgr5 and/or Bmi1 continuously replicate and generate differentiated cells throughout life. Previously， Paneth cells were suggested to constitute an epithelium-intrinsic niche that regulates the behavior of these stem cells. However， ablating Paneth cells has no effect on maintenance of functional stem cells. Here， we demonstrate definitively that a small subset of mesenchymal， subepithelial cells expressing the winged-helix transcription factor Foxl1 are a critical component of the intestinal stem cell niche.
Intestinal epithelial stem cells that express Lgr5 and/or Bmi1 continuously replicate and generate differentiated cells throughout life. Previously， Paneth cells were suggested to constitute an epithelium-intrinsic niche that regulates the behavior of these stem cells. However， ablating Paneth cells has no effect on maintenance of functional stem cells. Here， we demonstrate definitively that a small subset of mesenchymal， subepithelial cells expressing the winged-helix transcription factor Foxl1 are a critical component of the intestinal stem cell niche.
