Macrophage Tim-3 maintains intestinal homeostasis in DSS-induced colitis by suppressing neutrophil necroptosis
Fangfei Wang,
Feng Zhou,
Jianxiang Peng,
Hao Chen,
Jinliang Xie,
Cong Liu,
Huifang Xiong,
Sihai Chen,
Guohui Xue,
Xiaojiang Zhou,
Yong Xie
Affiliations
Fangfei Wang
Department of Gastroenterology, Digestive Disease Hospital, The First Affiliated Hospital of Nanchang University, Jiangxi Medical College, Nanchang University, Nanchang, Jiangxi Province, China; Institute of Digestive Disease, The First Affiliated Hospital of Nanchang University, Jiangxi Medical College, Nanchang University, Nanchang, Jiangxi Province, China
Feng Zhou
Department of Gastroenterology, Digestive Disease Hospital, The First Affiliated Hospital of Nanchang University, Jiangxi Medical College, Nanchang University, Nanchang, Jiangxi Province, China; Institute of Digestive Disease, The First Affiliated Hospital of Nanchang University, Jiangxi Medical College, Nanchang University, Nanchang, Jiangxi Province, China
Jianxiang Peng
Department of Gastroenterology, Digestive Disease Hospital, The First Affiliated Hospital of Nanchang University, Jiangxi Medical College, Nanchang University, Nanchang, Jiangxi Province, China; Institute of Digestive Disease, The First Affiliated Hospital of Nanchang University, Jiangxi Medical College, Nanchang University, Nanchang, Jiangxi Province, China
Hao Chen
Department of Gastroenterology, Digestive Disease Hospital, The First Affiliated Hospital of Nanchang University, Jiangxi Medical College, Nanchang University, Nanchang, Jiangxi Province, China; Institute of Digestive Disease, The First Affiliated Hospital of Nanchang University, Jiangxi Medical College, Nanchang University, Nanchang, Jiangxi Province, China
Jinliang Xie
Department of Gastroenterology, Digestive Disease Hospital, The First Affiliated Hospital of Nanchang University, Jiangxi Medical College, Nanchang University, Nanchang, Jiangxi Province, China; Institute of Digestive Disease, The First Affiliated Hospital of Nanchang University, Jiangxi Medical College, Nanchang University, Nanchang, Jiangxi Province, China
Cong Liu
Department of Gastroenterology, Digestive Disease Hospital, The First Affiliated Hospital of Nanchang University, Jiangxi Medical College, Nanchang University, Nanchang, Jiangxi Province, China; Institute of Digestive Disease, The First Affiliated Hospital of Nanchang University, Jiangxi Medical College, Nanchang University, Nanchang, Jiangxi Province, China
Huifang Xiong
Department of Gastroenterology, Digestive Disease Hospital, The First Affiliated Hospital of Nanchang University, Jiangxi Medical College, Nanchang University, Nanchang, Jiangxi Province, China; Institute of Digestive Disease, The First Affiliated Hospital of Nanchang University, Jiangxi Medical College, Nanchang University, Nanchang, Jiangxi Province, China
Sihai Chen
Department of Gastroenterology, Digestive Disease Hospital, The First Affiliated Hospital of Nanchang University, Jiangxi Medical College, Nanchang University, Nanchang, Jiangxi Province, China; Institute of Digestive Disease, The First Affiliated Hospital of Nanchang University, Jiangxi Medical College, Nanchang University, Nanchang, Jiangxi Province, China
Guohui Xue
Department of Clinical Laboratory, Affiliated Jiujiang Hospital of Nanchang University, Jiujiang, Jiangxi Province, China
Xiaojiang Zhou
Department of Gastroenterology, Digestive Disease Hospital, The First Affiliated Hospital of Nanchang University, Jiangxi Medical College, Nanchang University, Nanchang, Jiangxi Province, China; Institute of Digestive Disease, The First Affiliated Hospital of Nanchang University, Jiangxi Medical College, Nanchang University, Nanchang, Jiangxi Province, China
Yong Xie
Department of Gastroenterology, Digestive Disease Hospital, The First Affiliated Hospital of Nanchang University, Jiangxi Medical College, Nanchang University, Nanchang, Jiangxi Province, China; Institute of Digestive Disease, The First Affiliated Hospital of Nanchang University, Jiangxi Medical College, Nanchang University, Nanchang, Jiangxi Province, China; Corresponding author. Yongwai Street, Donghu District, Nanchang, Jiangxi Province, 330000, China
T-cell immunoglobulin domain and mucin domain-3 (Tim-3) is a versatile immunomodulator that protects against intestinal inflammation. Necroptosis is a type of cell death that regulates intestinal homeostasis and inflammation. The mechanism(s) underlying the protective role of macrophage Tim-3 in intestinal inflammation is unclear; thus, we investigated whether specific Tim-3 knockdown in macrophages drives intestinal inflammation via necroptosis. Tim-3 protein and mRNA expression were assessed via double immunofluorescence staining and single-cell RNA sequencing (sc-RNA seq), respectively, in the colonic tissues of patients with inflammatory bowel disease (IBD) and healthy controls. Macrophage-specific Tim3-knockout (Tim-3M−KO) mice were generated to explore the function and mechanism of Tim-3 in dextran sodium sulfate (DSS)-induced colitis. Necroptosis was blocked by pharmacological inhibitors of receptor-interacting protein kinase (RIP)1, RIP3, and reactive oxygen species (ROS). Additionally, in vitro experiments were performed to assess the mechanisms of neutrophil necroptosis induced by Tim-3 knockdown macrophages. Although Tim-3 is relatively inactive in macrophages during colon homeostasis, it is highly active during colitis. Compared to those in controls, Tim-3M−KO mice showed increased susceptibility to colitis, higher colitis scores, and increased pro-inflammatory mediator expression. Following the administration of RIP1/RIP3 or ROS inhibitors, a significant reduction in intestinal inflammation symptoms was observed in DSS-treated Tim-3M−KO mice. Further analysis indicated the TLR4/NF-κB pathway in Tim-3 knockdown macrophages mediates the TNF-α-induced necroptosis pathway in neutrophils. Macrophage Tim-3 regulates neutrophil necroptosis via intracellular ROS signaling. Tim-3 knockdown macrophages can recruit neutrophils and induce neutrophil necroptosis, thereby damaging the intestinal mucosal barrier and triggering a vicious cycle in the development of colitis. Our results demonstrate a protective role of macrophage Tim-3 in maintaining gut homeostasis by inhibiting neutrophil necroptosis and provide novel insights into the pathogenesis of IBD.