Oxidative stress and GPX2 control pancreatic vs non-pancreatic cell fate in human endoderm

The role of oxidative stress in cell fate decisions during human endoderm development remains poorly understood. Here, we show that GPX2, a key enzyme in the reactive oxygen species (ROS) scavenging pathway, plays a crucial role in directing pancreatic versus non-pancreatic cell fate decisions during in vitro human endoderm differentiation. Using hPSCs with GPX2 loss-of- or gain-of-function, we observed that GPX2-deficient cells exhibit a strong propensity to differentiate into liver-like cells, even under pancreatic-promoting conditions. Single-cell RNA sequencing, ATAC sequencing, and follow-up analyses revealed that GPX2 deficiency disrupts posterior foregut patterning, leading to the emergence of multilineage progenitors capable of generating liver- and intestine-like lineages. Phenotype rescue experiments demonstrated that manipulating oxidative stress levels by either inhibiting or promoting ROS production could mimic or revert the effects of GPX2 deficiency, respectively. Our findings highlight the critical role of oxidative stress in modulating developmental trajectories and suggest that GPX2 acts as a gatekeeper of pancreatic cell fate by influencing the expression of PDX1 and other lineage-specifying factors.