Qing-Re-Xing-Yu decoction confers intestinal barrier protection by reducing epithelial cell pyroptosis in experimental ulcerative colitis based on a NLRP3-GSDMD axis-dependent mechanism

Abstract Background Ulcerative colitis (UC) is a chronic inflammatory disease afflicting the colon, showing a rising incidence worldwide. Chinese medicinal formulae have been identified to be effective for the clinical treatment of UC yet the underlying mechanism remains under-studied. Purpose We herein investigate the molecular mechanistic actions of Qing-Re-Xing-Yu (QRXY) decoction on the intestinal barrier dysfunction of UC. Methods UC was induced in C57BL/6 mice by adding 3% dextran sulfate sodium (DSS) in the drinking water. Following this, the mice were administrated with QRXY decoction. Clinical symptoms were assessed, followed by determining the expression of NACHT, LRR, and PYD domains-containing protein 3 (NLRP3), inflammatory cytokines, Caco-2 cell viability, pyroptosis and permeability along with the lactate dehydrogenase (LDH) release in DSS-induced UC mice and NLRP3- or Gasdermin-D (GSDMD)-knockout Caco-2 cells. The GSDMD-overexpressing mouse model was constructed using the adeno-associated virus type 2 (AAV2) to examine its involvement in the role of QRXY in UC. Results QRXY decoction alleviated the DSS-induced intestinal mucosal damage in mice with UC. This effect of QRXY was associated with the downregulated activity of NLRP3 inflammasome. Mechanistic investigations showed that QRXY decoction impaired the DSS-induced Caco-2 cell pyroptosis and permeability in vitro by inhibiting the NLRP3-GSDMD signaling axis. Moreover, GSDMD overexpression attenuated the protective role of QRXY decoction in the intestinal barrier dysfunction. Conclusion Our study reveals that QRXY decoction restores intestinal barrier function via a NLRP3-GSDMD feedback loop, suggesting that NLRP3-GSDMD signaling inhibitor may serve as a adjuvant agent for UC, providing novel insight into the clinical application of QRXY decoction with better efficiency and smaller side effect.