Modelling human development and disease in pluripotent stem-cell-derived gastric organoids

The in vitro generation, from pluripotent stem cells, of three-dimensional human gastric organoids (hGOs) that contain a physiological gastric epithelium comprising both progenitor and differentiated cell types, and have expected functional characteristics is described, as is modelling the pathophysiological response of the human stomach to Helicobacter pylori using these hGOs. James Wells and colleagues describe the generation of three-dimensional human gastric organoids (hGOs) in vitro using human embryonic and induced pluripotent stem cells as starting material. The hGOs contain a physiological gastric epithelium that comprises both progenitor and differentiated cell types, and have expected functional characteristics. The authors then use their hGOs to model the pathophysiological response of human stomach to the gastric pathogen Helicobacter pylori. This new in vitro system might be helpful to elucidate the mechanisms underlying human stomach development and disease. Gastric diseases, including peptic ulcer disease and gastric cancer, affect 10% of the world’s population and are largely due to chronic Helicobacter pylori infection1,2,3. Species differences in embryonic development and architecture of the adult stomach make animal models suboptimal for studying human stomach organogenesis and pathogenesis4, and there is no experimental model of normal human gastric mucosa. Here we report the de novo generation of three-dimensional human gastric tissue in vitro through the directed differentiation of human pluripotent stem cells. We show that temporal manipulation of the FGF, WNT, BMP, retinoic acid and EGF signalling pathways and three-dimensional growth are sufficient to generate human gastric organoids (hGOs). Developing hGOs progressed through molecular and morphogenetic stages that were nearly identical to the developing antrum of the mouse stomach. Organoids formed primitive gastric gland- and pit-like domains, proliferative zones containing LGR5-expressing cells, surface and antral mucous cells, and a diversity of gastric endocrine cells. We used hGO cultures to identify novel signalling mechanisms that regulate early endoderm patterning and gastric endocrine cell differentiation upstream of the transcription factor NEUROG3. Using hGOs to model pathogenesis of human disease, we found that H. pylori infection resulted in rapid association of the virulence factor CagA with the c-Met receptor, activation of signalling and induction of epithelial proliferation. Together, these studies describe a new and robust in vitro system for elucidating the mechanisms underlying human stomach development and disease.