Amphiregulin Switches Progenitor Cell Fate for Lineage Commitment During Gastric Mucosal Regeneration

Background & Aims: Isthmic progenitors, tissue-specific stem cells in the stomach corpus, maintain mucosal homeostasis by balancing between proliferation and differentiation to gastric epithelial lineages. The progenitor cells rapidly adopt an active state in response to mucosal injury. However, it remains unclear how the isthmic progenitor cell niche is controlled during the regeneration of damaged epithelium. Methods: We recapitulated tissue recovery process after acute mucosal injury in the mouse stomach. BrdU incorporation was utilized to trace newly generated cells during the injury and recovery phases. To define epithelial lineage commitment process during recovery, we performed single cell RNA-sequencing on epithelial cells from the mouse stomachs. We validated the effects of amphiregulin (AREG) on the mucosal recovery, utilizing recombinant AREG treatment or AREG deficient mice. Results: We determined that an EGFR ligand, AREG, can control progenitor cell lineage commitment. Based on the identification of lineage-committed subpopulations in the corpus epithelium through single cell RNA-sequencing and BrdU incorporation, we showed that isthmic progenitors give rise to epithelial cell lineages through an ordered paradigm during mucosal regeneration. During recovery, AREG treatment promotes repopulation with parietal cells, while suppressing surface cell commitment of progenitors. In contrast, TGF-alpha did not alter parietal cell regeneration but did induce expansion of surface cell populations. AREG deficiency impairs parietal cell regeneration, but increases surface cell commitment. Conclusions: These data demonstrate that different EGF receptor ligands can distinctly regulate isthmic progenitor-driven mucosal regeneration and lineage commitment.