Epithelial-derived factors induce muscularis mucosa of human induced pluripotent stem cell-derived gastric organoids

Human gastric development has not been well studied. The generation of human pluripotent stem cell-derived gastric organoids (hGOs) comprising gastric marker-expressing epithelium without an apparent smooth muscle (SM) structure has been reported. We modified previously reported protocols to generate hGOs with muscularis mucosa (MM) from hiPSCs. Time course analyses revealed that epithelium development occurred prior to MM formation. Sonic hedgehog (SHH) and TGF-β1 were secreted by the epithelium. HH and TGF-β signal inhibition prevented subepithelial MM formation. A mechanical property of the substrate promoted SM differentiation around hGOs in the presence of TGF-β. TGF-β signaling was shown to influence the HH signaling and mechanical properties. In addition, clinical specimen findings suggested the involvement of TGF-β signaling in MM formation in recovering gastric ulcers. HH and TGF-β signaling from the epithelium to the stroma and the mechanical properties of the subepithelial environment may influence the emergence of MM in human stomach tissue. [Display omitted] •We successfully induce hGOs with MM by culturing for 8 weeks•The emergence of MM occurs after epithelial maturation•HH, TGF-β, and the mechanical environment are suggested to be involved in MM formation In this article, Aoi and colleagues successfully induce hiPSC-derived human gastric organoids with muscularis mucosa (MM), which allow us to investigate human gastric MM development. A time course analysis revealed that MM differentiates after epithelial maturation. Hedgehog and TGF-β signaling from the epithelium as well as the mechanical environment may be involved in the MM formation of human stomach tissue