Mingxia Zhou1,2, Jing He3, Yingying Shi1,2, Xiaoman Liu1,2, Shangjian Luo1,2, Cheng Cheng2, Wensong Ge1, Chunying Qu1, Peng Du4, Yingwei Chen1,2. 1. Department of Gastroenterology, Xinhua Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China. 2. Shanghai Key Laboratory of Pediatric Gastroenterology and Nutrition, Shanghai, China. 3. Department of General Surgery, Huashan Hospital, Fudan University, Shanghai, China. 4. Department of Colorectal Surgery, Xinhua Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.
Abstract
BACKGROUND AND AIMS: There is evidence for a disturbed necroptosis function in many inflammatory diseases but its role in inflammatory bowel diseases (IBD) and the underlying mechanisms are unclear. Here, we studied the functional significance and molecular mechanisms of ABIN3, a ubiquitin-binding protein, in regulating the ubiquitination and activation of necroptosis in IBD. METHODS: The expression of necroptosis hallmarks and ABIN3 were assessed in inflamed samples of IBD patients, dextran sodium sulfate (DSS)-induced colitis models and azoxymethane (AOM)/DSS models in mice. ABIN3 were overexpressed and silenced to explore its function in regulating necroptosis, inflammation and intestinal barrier function. Immuoprecipitiation (IP) and co-IP assays were performed to investigate the crosstalk between ABIN3 and deubiquitinating enzyme A20, and the mechanisms of coordinating ubiquitination modification to regulate necroptosis. RESULTS: Excessive necroptosis is an important contributory factor towards the uncontrolled inflammation and intestinal barrier defects in IBD and experimental colitis. Blocking necroptosis by Nec-1s or GSK'872 significantly prevented cell death and alleviated DSS-induced colitis in vivo, whereas in AOM/DSS model, necroptosis inhibitors aggravated the severity of colitis-associated colon carcinogenesis (CAC). Mechanistically, ABIN3 is rapidly recruited to the TNF-RSC complex, which interacts and coordinates with deubiquitinating enzyme A20 to control the K63 deubiquitination modification and subsequent activation of the critical necroptosis kinase, RIPK3, to suppress necroptosis. CONCLUSIONS: ABIN3 regulates inflammatory response and intestinal barrier function by interacting with A20 and coordinating the K63 deubiquitination modification of necroptosis in IBD. Published by Oxford University Press on behalf of European Crohn’s and Colitis Organisation (ECCO) 2020. This work is written by US Government employee and is in the public domain in the US.
BACKGROUND AND AIMS: There is evidence for a disturbed necroptosis function in many inflammatory diseases but its role in inflammatory bowel diseases (IBD) and the underlying mechanisms are unclear. Here, we studied the functional significance and molecular mechanisms of ABIN3, a ubiquitin-binding protein, in regulating the ubiquitination and activation of necroptosis in IBD. METHODS: The expression of necroptosis hallmarks and ABIN3 were assessed in inflamed samples of IBDpatients, dextran sodium sulfate (DSS)-induced colitis models and azoxymethane (AOM)/DSS models in mice. ABIN3 were overexpressed and silenced to explore its function in regulating necroptosis, inflammation and intestinal barrier function. Immuoprecipitiation (IP) and co-IP assays were performed to investigate the crosstalk between ABIN3 and deubiquitinating enzyme A20, and the mechanisms of coordinating ubiquitination modification to regulate necroptosis. RESULTS: Excessive necroptosis is an important contributory factor towards the uncontrolled inflammation and intestinal barrier defects in IBD and experimental colitis. Blocking necroptosis by Nec-1s or GSK'872 significantly prevented cell death and alleviated DSS-induced colitis in vivo, whereas in AOM/DSS model, necroptosis inhibitors aggravated the severity of colitis-associated colon carcinogenesis (CAC). Mechanistically, ABIN3 is rapidly recruited to the TNF-RSC complex, which interacts and coordinates with deubiquitinating enzyme A20 to control the K63 deubiquitination modification and subsequent activation of the critical necroptosis kinase, RIPK3, to suppress necroptosis. CONCLUSIONS:ABIN3 regulates inflammatory response and intestinal barrier function by interacting with A20 and coordinating the K63 deubiquitination modification of necroptosis in IBD. Published by Oxford University Press on behalf of European Crohn’s and Colitis Organisation (ECCO) 2020. This work is written by US Government employee and is in the public domain in the US.