Gasdermin E-mediated intestinal epithelial pyroptosis promotes chemically induced colitis in mice

Gasdermin E (GSDME) is a newly identified pyroptosis executioner and is upregulated in the intestinal epithelial cell (IEC) of ulcerative colitis (UC) patients. However, the effects of epithelial GSDME on UC remain unknown.

Bone marrow chimera experiments were performed to investigate the role of GSDME in nonhematopoietic cells, mainly including IECs. An FITC-dextran assay was used to assess the integrity of the intestinal epithelial barrier.

Gsdme chimeras that were reconstituted with wild-type bone marrow cells exhibited lower weight loss, disease activity index, colon shortening, and histology scores than wild-type chimeras after treatment with dextran sulfate sodium (DSS). However, Gsdme ^+/+ chimeras that were reconstituted with Gsdme-deficient bone marrow cells were not protected from DSS-induced colitis compared with wild-type chimeras. Importantly, DSS treatment activated Caspase-3 and cleaved GSDME to generate GSDME-N terminal fragments that are responsible for the induction of pyroptosis in IECs, but not in the intestinal lamina propria cell. Additionally, GSDME deficiency inhibited DSS-induced disruption of the intestinal epithelial barrier. Mechanistically, GSDME-mediated IEC pyroptosis is dependent on Caspase-3 activation, which is supported by the observation that the Caspase-3 inhibitor Z-DEVD-FMK inhibited DSS-induced GSDME cleavage in IECs.

We show that GSDME-mediated epithelial pyroptosis contributes to the development of DSS-induced colitis by promoting intestinal inflammation and disrupting the intestinal epithelial barrier.