Celastrol ameliorates ulcerative colitis by inhibiting HSP90-mediated necroptosis of intestinal epithelial cells.

INTRODUCTION: Ulcerative colitis (UC) is a chronic inflammatory bowel disease characterized by intestinal barrier dysfunction and epithelial cell death. Necroptosis of intestinal epithelial cells (IECs) mediated by the RIPK1/RIPK3/MLKL pathway has emerged as a key driver of UC progression. Celastrol, a bioactive compound from Celastrus wilfordii, has shown anti-inflammatory potential, but its effect on necroptosis in UC remains unclear. METHODS: A dextran sulfate sodium (DSS)-induced UC mouse model and a TSZ-induced HT-29 cell necroptosis model were established. Disease activity, colon length, histology, mucus barrier integrity, and tight junction protein expression were evaluated. Western blotting, immunofluorescence, qRT-PCR, and a cellular thermal shift assay (CESTA) were used to assess necroptosis and potential targeting of HSP90. RESULTS: Celastrol significantly improved body weight, disease activity index, and colon length, while restoring mucus secretion and tight junction proteins (ZO-1, Occludin, Muc-2). It reduced phosphorylation of RIPK1, RIPK3, and MLKL both in vivo and in vitro, decreased pro-inflammatory cytokines (TNF-α, IL-1β, IL-6), and attenuated TUNEL-positive IEC death. CESTA indicated that celastrol increased HSP90 thermal stability, suggesting HSP90 engagement. DISCUSSION: Celastrol ameliorates DSS-induced colitis by inhibiting HSP90-mediated necroptosis of intestinal epithelial cells, supporting its potential as a candidate for UC therapy.