Regulation of Parietal Cell Homeostasis by Bone Morphogenetic Protein Signaling

Area of Science:

• Gastroenterology
• Cell Biology
• Molecular Biology

Background:

• Bone morphogenetic protein (BMP) signaling is crucial for maintaining gastric epithelial homeostasis.
• Loss of BMP signaling in the stomach, via noggin expression, leads to parietal cell (PC) loss and metaplasia.
• The specific role of BMP signaling within PCs in regulating epithelial homeostasis remains unclear.

Purpose of the Study:

• To investigate the consequences of cell-specific BMP signaling inhibition in gastric parietal cells (PCs).
• To determine if disrupting BMP signaling in PCs leads to gastric epithelial aberrations and metaplasia.

Main Methods:

• Generated mice with conditional deletion of BMP receptor 1a (Bmpr1a) specifically in PCs (H/K-Cre;Bmpr1a mice).
• Analyzed gastric mucosa morphology, cell distribution (H+/K+-ATPase, IF, Ki-67), and mucin expression (UEA-1, GS-II).
• Utilized RNA-Seq on purified PCs from noggin-expressing mice to identify transcriptomic changes.

Main Results:

• Mice with inhibited BMP signaling in PCs showed increased epithelial proliferation and transitional cells.
• Expansion of Ulex Europaeus Agglutinin 1-positive cells and altered mucin expression were observed.
• PC-specific BMP signaling loss induced markers of spasmolytic polypeptide-expressing metaplasia.

Conclusions:

• Parietal cell-specific loss of BMP signaling disrupts gastric epithelial homeostasis.
• This disruption promotes the development of metaplasia, a preneoplastic condition.