IL22 is a cytokine that plays a critical role in modulating tissue responses during inflammation and maintaining epithelial barrier function 1. Unlike most cytokines, IL22 does not directly affect immune cells but signals through a heterodimeric receptor composed of IL22RA1 and IL10RB on non-immune cells 23. Ligand binding activates JAK1/TYK2 and STAT3, promoting cell survival and proliferation through STAT3, ERK1/2, and PI3K/AKT pathways 45. IL22 is essential for intestinal immunity and tissue repair. It is required for Paneth cell formation and induces expression of antimicrobial peptides and host defense genes in multiple intestinal cell types 6. IL22 production by CD4+ T cells and innate lymphoid cells is promoted by microbiota-derived short-chain fatty acids through GPR41 and HDAC inhibition, maintaining intestinal homeostasis 7. In intestinal epithelial cells, IL22 signaling in MATH1+ goblet and progenitor cells promotes mucin O-glycosylation and is essential for barrier maintenance and tissue regeneration during colitis 8. Clinically, IL22 dysregulation is implicated in inflammatory bowel disease, where loss-of-function IL10RB mutations abolish Paneth cell formation 6. Additionally, IL22 has emerged as a protective factor against stress-induced anxiety through direct suppression of septal neuron activation 9, and reduced IL22 levels are observed in clinical depression 9.