Visualization of a Short-Range Wnt Gradient in the Intestinal Stem-Cell Niche

Nature. 2016 Feb 18;530(7590):340-3. doi: 10.1038/nature16937. Epub 2016 Feb 10.

Abstract

Mammalian Wnt proteins are believed to act as short-range signals, yet have not been previously visualized in vivo. Self-renewal, proliferation and differentiation are coordinated along a putative Wnt gradient in the intestinal crypt. Wnt3 is produced specifically by Paneth cells. Here we have generated an epitope-tagged, functional Wnt3 knock-in allele. Wnt3 covers basolateral membranes of neighbouring stem cells. In intestinal organoids, Wnt3-transfer involves direct contact between Paneth cells and stem cells. Plasma membrane localization requires surface expression of Frizzled receptors, which in turn is regulated by the transmembrane E3 ligases Rnf43/Znrf3 and their antagonists Lgr4-5/R-spondin. By manipulating Wnt3 secretion and by arresting stem-cell proliferation, we demonstrate that Wnt3 mainly travels away from its source in a cell-bound manner through cell division, and not through diffusion. We conclude that stem-cell membranes constitute a reservoir for Wnt proteins, while Frizzled receptor turnover and 'plasma membrane dilution' through cell division shape the epithelial Wnt3 gradient.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Alleles
  • Animals
  • Cell Adhesion
  • Cell Division
  • Cell Membrane / metabolism*
  • Diffusion
  • Female
  • Frizzled Receptors / metabolism
  • Gene Knock-In Techniques
  • Intercellular Signaling Peptides and Proteins / metabolism
  • Intestinal Mucosa / cytology*
  • Male
  • Mice
  • Organoids / cytology
  • Organoids / metabolism
  • Paneth Cells / cytology
  • Paneth Cells / metabolism
  • Receptors, G-Protein-Coupled / metabolism
  • Stem Cell Niche*
  • Stem Cells / cytology*
  • Stem Cells / metabolism*
  • Ubiquitin-Protein Ligases / metabolism
  • Wnt Signaling Pathway*
  • Wnt3 Protein / genetics
  • Wnt3 Protein / metabolism*

Substances

  • Frizzled Receptors
  • Intercellular Signaling Peptides and Proteins
  • LGR4 protein, mouse
  • Receptors, G-Protein-Coupled
  • Wnt3 Protein
  • Wnt3 protein, mouse
  • RNF43 protein, mouse
  • Ubiquitin-Protein Ligases
  • Znrf3 protein, mouse