Spatiotemporal dynamics of lineage-specific epithelial maturation in the developing mouse stomach

At birth, the gastric epithelium is immature and progressively matures during postnatal development to establish adult tissue architecture and function. Although this process has been investigated at functional, proteomic and transcriptomic levels, the precise temporal and spatial dynamics by which individual epithelial lineages initiate differentiation, exit proliferative states and establish adult homeostasis remain incompletely understood. Here, we performed a comprehensive immunofluorescence analysis of the mouse stomach from mid-gestation through adulthood, examining fetal markers, lineage-specific functional epithelial markers, and the proliferation marker KI67. By integrating functional epithelial marker expression with proliferative status, we delineated distinct maturation trajectories for pit, parietal, and chief cell lineages. Notably, parietal and chief cells exhibited a robust proliferative phase from late gestation to early postnatal stages, followed by a marked decline in proliferative activity, whereas pit cells showed the emergence of proliferative progenitors primarily during later postnatal stages. Moreover, we identified region-specific differences in the timing of maturation between the corpus and the antrum. Together, our study establishes a spatiotemporal in situ atlas of gastric epithelial maturation and provides a framework for understanding lineage- and region- specific mechanisms governing postnatal gastric development.