IL-22 Increases Proglucagon-expressing Enteroendocrine Cells via STAT3 in Human iPSC-derived Intestinal Epithelium

Intestinal epithelial differentiation is tightly regulated to maintain tissue homeostasis and systemic metabolic function. Although the intrinsic transcriptional programs governing enteroendocrine cell (EEC) development have been characterized extensively, the role of extrinsic immune signals in directing lineage specification is not completely understood. In particular, how cytokine signaling influences differentiation of EEC subtypes remains unclear. Here, we investigated the role of interleukin-22 (IL-22) in EEC differentiation using human induced pluripotent stem cell-derived intestinal organoids and in vivo models. IL-22 selectively increased proglucagon (GCG) expression and the number of glucagon-like peptide-1 (GLP-1)-positive EECs without affecting other EEC markers. This effect was associated with enhanced expression of the lineage-related transcription factors neurogenin 3 and forkhead box A2. Pharmacological inhibition of signal transducer and activator of transcription 3 (STAT3) signaling attenuated the IL-22-induced increases in GCG expression and GLP-1-positive cell abundance, indicating a role of STAT3 in mediating these effects. Mechanistically, relatively high expression of IL-22 receptor subunit alpha 1 in undifferentiated epithelial cells was associated with STAT3 activation induced by IL-22. Consistent with these findings, in vivo IL-22 administration increased intestinal GCG expression and GLP-1 levels in the circulation and intestinal tissue. Importantly, our findings indicate that IL-22 does not globally promote EEC differentiation but rather selectively directs epithelial lineage commitment toward the GCG-positive EEC fate. These results suggest that IL-22/STAT3 signaling induces human intestinal epithelial differentiation into GCG-positive EECs and may represent a strategy for modulating epithelial cell fate to influence systemic metabolic homeostasis.