Type III interferons induce pyroptosis in gut epithelial cells and impair tissue repair upon intestinal injury.

Tissue damage and repair are hallmarks of the inflammatory process. Despite a wealth of information on the mechanisms that govern tissue damage, mechanistic insight on how inflammatory mediators affect repair is lacking. Here, we investigated how interferons influence tissue repair after damage to the intestinal mucosa driven by inflammation or genotoxicity. We found that type III, but not type I or II, interferons delay epithelial cell regeneration by inducing the upregulation of Z-DNA-binding protein 1 (ZBP1). Z-nucleic acids formed during the damage and repair process are then sensed by ZBP-1, leading to Caspase-8 activation, and cleavage of Gasdermin C (GSDMC). Cleaved GSDMC drives epithelial cell death by pyroptosis and delays the re-epithelialization of the large or small intestine after colitis or irradiation, respectively. We also found that the type III interferon/ZBP1/Caspase-8/GSDMC pathway is activated in patients with inflammatory bowel disease (IBD). Our findings highlight a molecular signaling cascade initiated by type III interferons that delays intestinal tissue repair, which has important implications for IBD patients or individuals exposed to radiation therapies.