TY - JOUR
T1 - Depletion of the Colonic Epithelial Precursor Cell Compartment Upon Conditional Activation of the Hedgehog Pathway
AU - van Dop, Willemijn A.
AU - Uhmann, Anja
AU - Wijgerde, Mark
AU - Sleddens-Linkels, Esther
AU - Heijmans, Jarom
AU - Offerhaus, G. Johan
AU - van den Bergh Weerman, Marius A.
AU - Boeckxstaens, Guy E.
AU - Hommes, Daan W.
AU - Hardwick, James C.
AU - Hahn, Heidi
AU - van den Brink, Gijs R.
PY - 2009/6
Y1 - 2009/6
N2 - Background & Aims: The intestinal epithelium is a homeostatic system in which differentiated cells are in dynamic equilibrium with rapidly cycling precursor cells. Wnt signaling regulates intestinal epithelial precursor cell fate and proliferation. Homeostatic systems exist by virtue of negative feedback loops, and we have previously identified the Hedgehog (Hh) pathway as a potential negative feedback signal in the colonic epithelium. Indian hedgehog (Ihh) is produced by the differentiated enterocytes and negatively regulates Wnt signaling in intestinal precursor cells. We studied the role of members of the Hh signaling family in the intestine using a conditional genetic approach. Methods: We inactivated the Hh receptor Patched1 (Ptch1) in adult mice, resulting in constitutive activation of the Hh signaling pathway. Effects on colonic mucosal homeostasis were examined. Colon tissues were examined by immunohistochemistry, in situ hybridization, transmission electron microscopy, and real-time polymerase chain reaction. Results: Ihh but not Sonic hedgehog (Shh) was expressed in colonic epithelium. Expression of Ptch1 and Gli1 was restricted to the mesenchyme. Constitutive activation of Hh signaling resulted in accumulation of myofibroblasts and colonic crypt hypoplasia. A reduction in the number of epithelial precursor cells was observed with premature development into the enterocyte lineage and inhibition of Wnt signaling. Activation of Hh signaling resulted in induction of the expression of bone morphogenetic proteins (Bmp) and increased Bmp signaling in the epithelium. Conclusions: Hh signaling acts in a negative feedback loop from differentiated cells via the mesenchyme to the colonic epithelial precursor cell compartment in the adult mouse.
AB - Background & Aims: The intestinal epithelium is a homeostatic system in which differentiated cells are in dynamic equilibrium with rapidly cycling precursor cells. Wnt signaling regulates intestinal epithelial precursor cell fate and proliferation. Homeostatic systems exist by virtue of negative feedback loops, and we have previously identified the Hedgehog (Hh) pathway as a potential negative feedback signal in the colonic epithelium. Indian hedgehog (Ihh) is produced by the differentiated enterocytes and negatively regulates Wnt signaling in intestinal precursor cells. We studied the role of members of the Hh signaling family in the intestine using a conditional genetic approach. Methods: We inactivated the Hh receptor Patched1 (Ptch1) in adult mice, resulting in constitutive activation of the Hh signaling pathway. Effects on colonic mucosal homeostasis were examined. Colon tissues were examined by immunohistochemistry, in situ hybridization, transmission electron microscopy, and real-time polymerase chain reaction. Results: Ihh but not Sonic hedgehog (Shh) was expressed in colonic epithelium. Expression of Ptch1 and Gli1 was restricted to the mesenchyme. Constitutive activation of Hh signaling resulted in accumulation of myofibroblasts and colonic crypt hypoplasia. A reduction in the number of epithelial precursor cells was observed with premature development into the enterocyte lineage and inhibition of Wnt signaling. Activation of Hh signaling resulted in induction of the expression of bone morphogenetic proteins (Bmp) and increased Bmp signaling in the epithelium. Conclusions: Hh signaling acts in a negative feedback loop from differentiated cells via the mesenchyme to the colonic epithelial precursor cell compartment in the adult mouse.
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U2 - 10.1053/j.gastro.2009.02.068
DO - 10.1053/j.gastro.2009.02.068
M3 - Article
C2 - 19272384
AN - SCOPUS:66149103193
SN - 0016-5085
VL - 136
JO - Gastroenterology
JF - Gastroenterology
IS - 7
ER -