Fig. 7: The interaction between BMP and Wnt signaling establishes the different epithelial turnover rates and villus length in the proximal and distal small intestine.
From: Positional BMP signaling orchestrates villus length in the small intestine
BMP signaling exhibits a spatial gradient from the proximal duodenum to the distal ileum. As BMP signaling increases from the proximal to distal segment, Wnt signaling activity remains relatively constant. BMP signaling inhibits cell proliferation, promotes epithelial cell apoptosis by inhibiting integrin expression, and suppresses Wnt signaling. This gradient of BMP signaling correlates with the gradual reduction in villus length from the proximal to distal small intestine. Along the crypt-villus axis, increased BMP signaling coupled with its negative feedback on Wnt signaling attenuates cell proliferation as villi reach a certain length. Furthermore, the positive feedback of Wnt signaling on BMP signaling prevents excessive proliferation to maintain stable villus length (Created in BioRender. Liu (2025) https://BioRender.com/u0fu7hg).
