Epithelial NF-κB shapes protective Treg cell responses to restrain intestinal inflammation.

Inflammation resolution depends on coordinated communication between tissue compartments, yet how the intestinal epithelium shapes its immune microenvironment remains poorly understood. Here, using colonic biopsies from patients with ulcerative colitis (UC) and mouse models enabling tissue-wide visualization of NF-κB activity, we combine single-cell RNA sequencing and secretome analysis to define epithelial communication during colitis. We show that, paradoxically, the NF-κB-driven pro-inflammatory secretome of intestinal epithelial cells (IECs) is essential for recovery and prevents unrestrained inflammation. Mechanistically, epithelial NF-κB promotes CCL22-dependent regulatory T cell (Treg cell) recruitment and promotes a tolerogenic, pro-repair cell state, accompanied by induction of the lipid-metabolism-associated GDPD3 and CCR4. In UC, epithelial NF-κB is not uniformly activated but instead induces a selective pro-inflammatory transcriptional program while repressing targets regulating T cell recruitment. Thus, we identify dynamic epithelial-immune communication and demonstrate a protective IEC NF-κB-Treg cell axis important for resolution of intestinal inflammation.