Visualization of a short-range Wnt gradient in the intestinal stem-cell niche

• Published in: Nature (London) Vol. 530; no. 7590; pp. 340 - 343
• Main Authors: Farin, Henner F., Jordens, Ingrid, Mosa, Mohammed H., Basak, Onur, Korving, Jeroen, Tauriello, Daniele V. F., de Punder, Karin, Angers, Stephane, Peters, Peter J., Maurice, Madelon M., Clevers, Hans
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 18.02.2016; Nature Publishing Group
• Subjects: 631/136/2139; 631/532/2437; 631/80/86; 631/80/86/2368; Alleles; Animals; Cell Adhesion; Cell Division; Cell Membrane - metabolism; Diffusion; Drosophila; Female; Frizzled Receptors - metabolism; Gene expression; Gene Knock-In Techniques; Humanities and Social Sciences; Influence; Insects; Intercellular Signaling Peptides and Proteins - metabolism; Intestinal Mucosa - cytology; letter; Ligases; Male; Membranes; Mice; multidisciplinary; Organoids - cytology; Organoids - metabolism; Paneth Cells - cytology; Paneth Cells - metabolism; Physiological aspects; Proteins; Receptors, G-Protein-Coupled - metabolism; Science; Stem Cell Niche; Stem cell research; Stem cells; Stem Cells - cytology; Stem Cells - metabolism; Studies; Ubiquitin-Protein Ligases - metabolism; Vertebrates; Wnt Signaling Pathway; Wnt3 Protein - genetics; Wnt3 Protein - metabolism
• ISSN: 0028-0836; 1476-4687; 1476-4687
• DOI: 10.1038/nature16937

Generation of an epitope-tagged, functional Wnt3 knock-in allele, the signal produced by Paneth cells to regulate intestinal stem cells. Wnt signalling in the intestinal crypt The Wnt signalling pathway is a key mediator of the intestinal stem-cell niche and is involved in maintaining the intestinal crypt structures in the epithelial lining of the small intestine in mice. Although Wnt3 is secreted by Paneth cells to act on intestinal stem cells, it has not been possible to follow its fate in vivo , so it is not clear if its propagation involves a gradient set by diffusion. Henner Farin et al . have generated a tagged Wnt3 and find that it binds to the basolateral membrane of intestinal stem cells in an organoid-based system, and is propagated through partition of cell membrane by cell division rather than through diffusion. Mammalian Wnt proteins are believed to act as short-range signals 1 , 2 , 3 , 4 , yet have not been previously visualized in vivo . Self-renewal, proliferation and differentiation are coordinated along a putative Wnt gradient in the intestinal crypt 5 . Wnt3 is produced specifically by Paneth cells 6 , 7 . 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.