RNF168 promotes chronic colitis through ANXA7-mediated autophagy and NLRP3-driven pyroptosis

This study aimed to investigate the roles of ANXA7 and its upstream regulator RNF168 in Crohn's disease (CD) progression, focusing on their interaction with inflammation and intestinal mucosal barrier disruption. Colon tissues from CD patients, including inflamed and uninflamed tissues, were analyzed to assess ANXA7 expression. The biological functions of ANXA7 were studied in vitro using LPS/ATP-stimulated NCM460 cells, employing ANXA7 knockdown and overexpression experiments. Protein-protein interactions were examined using co-immunoprecipitation (Co-IP) and mass spectrometry. The regulatory role of RNF168 in ANXA7 degradation was explored through Co-IP and ubiquitination assays. The effects of RNF168 and ANXA7 on autophagy and NLRP3 inflammasome-induced pyroptosis were assessed. In vivo experiments were conducted using IL-10 knockout (KO) mice, RNF168^{flox/flox; Villin-Cre} mice with TNBS-induced colitis, and organoids to investigate the therapeutic potential of RNF168 and ANXA7 manipulation. ANXA7 expression was significantly reduced in inflamed tissues and correlated with CD-related inflammatory markers. RNF168 promoted the ubiquitination and degradation of ANXA7, thereby suppressing autophagy and inducing NLRP3 inflammasome-mediated pyroptosis. The in vitro and in vivo biological functions of sh-RNF168 were rescued by sh-ANXA7. ELK1 was identified as a key transcription factor regulating RNF168 expression, linking transcriptional regulation with inflammation and disease progression. Our findings suggest a mechanistic model where ELK1 upregulates RNF168, leading to ANXA7 degradation, suppression of autophagy, and enhanced pyroptosis, thereby promoting CD progression and intestinal barrier disruption. Targeting the RNF168-ANXA7 axis offers a potential therapeutic strategy for CD.