Intestinal barrier: Molecular pathways and modifiers

Figure 1 The molecular regulatory pathways in intestinal epithelial homeostasis. Wnt signaling promotes the proliferation of TA/stem cells and drives Paneth cell maturation. Notch signaling cooperates with Wnt to drive proliferation of intestinal stem cells and regulates maintenance of undifferentiated TA/stem cells. Hippo and bone morphogenetic protein (BMP) signaling inhibits proliferation and induces maturation of all secretory cell types. Hedgehog signaling activates the expression of BMP in the mesenchyme.