Abstract
Cell fate decisions in human endoderm development are tightly regulated, yet the role of metabolic products remains elusive. The endodermal posterior foregut gives rise to pancreas, liver, and intestine. Here, we identify Glutathione Peroxidase 2 as a critical regulator of human posterior foregut differentiation, revealing oxidative stress as a key determinant of pancreatic versus non-pancreatic cell fate. Cells lacking Glutathione Peroxidase 2 under pancreas-promoting conditions differentiate also into hepatic-like progenitors. Through bulk and single-cell transcriptomics, chromatin accessibility profiling, and functional studies, we reveal that Glutathione Peroxidase 2 orchestrates lineage commitment by regulating key transcription factors, leading to emergence of multilineage liver and intestinal progenitors. Mechanistically, Glutathione Peroxidase 2 deficiency triggers extracellular matrix remodeling, activating bone morphogenetic protein signaling and skewing differentiation from the pancreatic lineage. Manipulating oxidative stress recapitulates or rescues Glutathione Peroxidase 2 loss effects, establishing oxidative stress as a gatekeeper of pancreatic fate. Controlling oxidative stress during in vitro differentiation could advance regenerative medicine applications.