Fig. 1

Schematic diagram of crypt-villus unit in the adult mammalian intestine and a model for the communications between cell death on the villus and cell proliferation in the crypt. Cell proliferation in the crypt leads to cell migrating toward the tip of the villus where most cell death occurs. The migrating cell will exert a”push” pressure on the adjacent cell above, e.g., the middle cell in the enlarged area near the tip of the villus). This may cause changes in cell–cell and/or cell-EMC interaction to facilitate cell death. Conversely, cell death on the villus will enhance upward migration of the cells in the crypt to replace the dying differentiated epithelial cells on the villus. This creates a “pull” tension/force to the adjacent cell below, e.g., the middle cell in the enlarged area near the crypt, thus leading to changes in cell–cell and/or cell-EMC interaction to facilitate cell proliferation