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Gastroenterology. 2014 Sep;147(3):655-666.e9. doi: 10.1053/j.gastro.2014.05.006. Epub 2014 May 20.

Indian Hedgehog mediates gastrin-induced proliferation in stomach of adult mice.

Author information

1
Department of Molecular and Cellular Physiology, University of Cincinnati College of Medicine, Cincinnati, Ohio.
2
The Physiological Laboratory, School of Biomedical Sciences, University of Liverpool, Liverpool, UK.
3
Division of Developmental Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio.
4
Division of Digestive and Liver Disease, Department of Medicine, Columbia University, College of Physicians and Surgeons, New York, New York.
5
Department of Medical Oncology, Dana-Farber Cancer Institute, and Department of Medicine, Harvard Medical School, Boston, Massachusetts.
6
Department of Molecular and Cellular Physiology, University of Cincinnati College of Medicine, Cincinnati, Ohio. Electronic address: yana.zavros@uc.edu.

Abstract

BACKGROUND & AIMS:

Loss of expression of Sonic Hedgehog (Shh) from parietal cells results in hypergastrinemia in mice, accompanied by increased expression of Indian Hedgehog (Ihh) and hyperproliferation of surface mucous cells. We investigated whether hypergastrinemia induces gastric epithelial proliferation by activating Ihh signaling in mice.

METHODS:

We studied mice with parietal cell-specific deletion of Shh (PC-Shh(KO)) and hypergastrinemia, crossed with gastrin-deficient (GKO) mice (PC-Shh(KO)/GKO). When mice were 3-4 months old, gastric tissues were collected and analyzed by histology, for incorporation of bromodeoxyuridine, and for expression of the surface mucous cell marker Ulex europaeus. PC-Shh(KO)/GKO mice were given gastrin infusions for 7 days; gastric surface epithelium was collected and expression of Ihh was quantified by laser capture microdissection followed by quantitative reverse transcriptase polymerase chain reaction. Mouse stomach-derived organoids were incubated with or without inhibitors of WNT (DKK1) or Smoothened (vismodegib) and then cocultured with immortalized stomach mesenchymal cells, to assess proliferative responses to gastrin.

RESULTS:

Gastric tissues from PC-Shh(KO)/GKO mice with hypergastrinemia had an expanded surface pit epithelium, indicated by a significant increase in numbers of bromodeoxyuridine- and Ulex europaeus-positive cells, but there was no evidence for hyperproliferation. Gastrin infusion of PC PC-Shh(KO)/GKO mice increased expression of Ihh and proliferation within the surface epithelium compared with mice given infusions of saline. In gastric organoids cocultured with immortalized stomach mesenchymal cells, antagonists of WNT and Smoothened inhibited gastrin-induced proliferation and WNT activity. Activity of WNT in media collected from immortalized stomach mesenchymal cells correlated with increased expression of glioma-associated oncogene homolog 1, and was inhibited by DKK1 or vismodegib.

CONCLUSIONS:

Ihh signaling mediates gastrin-induced proliferation of epithelial cells in stomachs of adult mice.

KEYWORDS:

Development; Gastric Epithelium; Signal Transduction; Tissue Regeneration

PMID:
24859162
PMCID:
PMC4211430
DOI:
10.1053/j.gastro.2014.05.006
[Indexed for MEDLINE]
Free PMC Article

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