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

Background: 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.

Methods: 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.

Results: 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.

Conclusions: 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.