The Hedgehog Hold on Homeostasis Ciara Metcalfe, Christian W. Siebel  Cell Stem Cell  Volume 17, Issue 5, Pages 505-506 (November 2015) DOI: 10.1016/j.stem.2015.10.010 Copyright © 2015 Elsevier Inc. Terms and Conditions

Figure 1 Hedgehog Signaling Sets Up an Epithelial-Mesenchymal Feedback Loop to Maintain Quiescence in the Adult Lung Shh, expressed primarily in the secretory cells of the airway epithelium, drives Hh pathway activity in the adjacent mesenchyme and maintains its quiescence. Epithelial injury attenuates the signal, which relieves the quiescent hold on the fibroblasts, enabling them to proliferate. Mesenchymal expansion is in turn associated with increased proliferation of the epithelial layer, reestablishing the source of Hh ligand and a return to quiescence. Cell Stem Cell 2015 17, 505-506DOI: (10.1016/j.stem.2015.10.010) Copyright © 2015 Elsevier Inc. Terms and Conditions