Signaling basis of gastric epithelial cell differentiation revealed by human and mouse organoids [RNA-Seq]

The directed differentiation of adult gastric stem cells into specific epithelial cell types is crucial for gastric homeostasis. Although it is well appreciated that the niche plays a critical role in gastric epithelium cell differentiation, the relevant molecular factors and the underlying regulatory mechanisms remain poorly understood. In this study, by combining the knowledge of the niche cells obtained from single-cell RNA sequencing and manipulation of signaling pathways, we achieved efficient differentiation of various gastric epithelial cell types in mouse and human gastric organoids. These in vitro differentiated cells showed a similar gene expression profile to those in gastric tissues. Specifically, we showed that BMP4 signaling stimulates parietal cell differentiation, EGF and BMP4 signaling work together to enhance pit cell differentiation, while TGF-β inhibition facilitates chief cell differentiation. In addition, the small molecule Isoxazole 9, which has been shown to stimulate differentiation of neuronal cells, pancreatic β-cells, and intestinal enteroendocrine cells, promotes parietal and endocrine cell differentiation in gastric organoids. Our data also revealed the different requirements of parietal and chief cell differentiation between mouse and human. Together, our findings provide a mechanistic insight into gastric epithelial cell differentiation and uncover its similarities and differences between mouse and human.