Wnt Ligands Secreted by Subepithelial Mesenchymal Cells Are Essential for the Survival of Intestinal Stem Cells and Gut Homeostasis
Tomas Valenta,
Bahar Degirmenci,
Andreas E. Moor,
Patrick Herr,
Dario Zimmerli,
Matthias B. Moor,
George Hausmann,
Claudio Cantù,
Michel Aguet,
Konrad Basler
Affiliations
Tomas Valenta
Institute of Molecular Life Sciences, University of Zurich, Winterthurerstr. 190, 8057 Zurich, Switzerland
Bahar Degirmenci
Institute of Molecular Life Sciences, University of Zurich, Winterthurerstr. 190, 8057 Zurich, Switzerland
Andreas E. Moor
Department of Molecular Cell Biology, Wolfson Building 623, Weizmann Institute of Science, Rehovot 76100, Israel
Patrick Herr
Institute of Molecular Life Sciences, University of Zurich, Winterthurerstr. 190, 8057 Zurich, Switzerland
Dario Zimmerli
Institute of Molecular Life Sciences, University of Zurich, Winterthurerstr. 190, 8057 Zurich, Switzerland
Matthias B. Moor
Department of Pharmacology and Toxicology, University of Lausanne, 1005 Lausanne, Switzerland
George Hausmann
Institute of Molecular Life Sciences, University of Zurich, Winterthurerstr. 190, 8057 Zurich, Switzerland
Claudio Cantù
Institute of Molecular Life Sciences, University of Zurich, Winterthurerstr. 190, 8057 Zurich, Switzerland
Michel Aguet
Swiss Institute for Experimental Cancer Research (ISREC), Ecole Polytechnique Fédérale de Lausanne (EPFL), School of Life Sciences, 1015 Lausanne, Switzerland
Konrad Basler
Institute of Molecular Life Sciences, University of Zurich, Winterthurerstr. 190, 8057 Zurich, Switzerland
Targeting of Wnt signaling represents a promising anti-cancer therapy. However, the consequences of systemically attenuating the Wnt pathway in an adult organism are unknown. Here, we globally prevent Wnt secretion by genetically ablating Wntless. We find that preventing Wnt signaling in the entire body causes mortality due to impaired intestinal homeostasis. This is caused by the loss of intestinal stem cells. Reconstitution of Wnt/β-catenin signaling via delivery of external Wnt ligands prolongs the survival of intestinal stem cells and reveals the essential role of extra-epithelial Wnt ligands for the renewal of the intestinal epithelium. Wnt2b is a key extra-epithelial Wnt ligand capable of promoting Wnt/β-catenin signaling and intestinal homeostasis. Wnt2b is secreted by subepithelial mesenchymal cells that co-express either Gli1 or Acta2. Subepithelial mesenchymal cells expressing high levels of Wnt2b are predominantly Gli1 positive.
