Graded BMP signaling within intestinal crypt architecture directs self-organization of the Wnt-secreting stem cell niche

Cell Stem Cell. 2023 Apr 6;30(4):433-449.e8. doi: 10.1016/j.stem.2023.03.004.

Abstract

Signals from the surrounding niche drive proliferation and suppress differentiation of intestinal stem cells (ISCs) at the bottom of intestinal crypts. Among sub-epithelial support cells, deep sub-cryptal CD81+ PDGFRAlo trophocytes capably sustain ISC functions ex vivo. Here, we show that mRNA and chromatin profiles of abundant CD81- PDGFRAlo mouse stromal cells resemble those of trophocytes and that both populations provide crucial canonical Wnt ligands. Mesenchymal expression of key ISC-supportive factors extends along a spatial and molecular continuum from trophocytes into peri-cryptal CD81- CD55hi cells, which mimic trophocyte activity in organoid co-cultures. Graded expression of essential niche factors is not cell-autonomous but dictated by the distance from bone morphogenetic protein (BMP)-secreting PDGFRAhi myofibroblast aggregates. BMP signaling inhibits ISC-trophic genes in PDGFRAlo cells near high crypt tiers; that suppression is relieved in stromal cells near and below the crypt base, including trophocytes. Cell distances thus underlie a self-organized and polar ISC niche.

Keywords: PDGFRA+ mesenchymal cells; colonic crypts; intestinal Wnt source; intestinal crypt structure and function; intestinal stem cell niche; mesenchymal niche compartments; trophocytes.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Cell Differentiation
  • Cell Proliferation
  • Intestinal Mucosa* / metabolism
  • Intestines
  • Mice
  • Signal Transduction
  • Stem Cell Niche*