Epithelial Gab1 calibrates RIPK3-dependent necroptosis to prevent intestinal inflammation
Jiaqi Xu, … , Zhinong Jiang, Xue Zhang
Jiaqi Xu, … , Zhinong Jiang, Xue Zhang
Published February 16, 2023
Citation Information: JCI Insight. 2023;8(6):e162701. https://doi.org/10.1172/jci.insight.162701.
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Research Article Gastroenterology Inflammation

Epithelial Gab1 calibrates RIPK3-dependent necroptosis to prevent intestinal inflammation

Abstract

As a hallmark of inflammatory bowel disease (IBD), elevated intestinal epithelial cell (IEC) death compromises the gut barrier, activating the inflammatory response and triggering more IEC death. However, the precise intracellular machinery that prevents IEC death and breaks this vicious feedback cycle remains largely unknown. Here, we report that Grb2-associated binder 1 (Gab1) expression is decreased in patients with IBD and inversely correlated with IBD severity. Gab1 deficiency in IECs accounted for the exacerbated colitis induced by dextran sodium sulfate owing to sensitizing IECs to receptor-interaction protein kinase 3–mediated (RIPK3-mediated) necroptosis, which irreversibly disrupted the homeostasis of the epithelial barrier and promoted intestinal inflammation. Mechanistically, Gab1 negatively regulated necroptosis signaling through inhibiting the formation of RIPK1/RIPK3 complex in response to TNF-α. Importantly, administration of RIPK3 inhibitor revealed a curative effect in epithelial Gab1-deficient mice. Further analysis indicated mice with Gab1 deletion were prone to inflammation-associated colorectal tumorigenesis. Collectively, our study defines a protective role for Gab1 in colitis and colitis-driven colorectal cancer by negatively regulating RIPK3-dependent necroptosis, which may serve as an important target to address necroptosis and intestinal inflammation–related disease.

Authors

Jiaqi Xu, Shihao Li, Wei Jin, Hui Zhou, Tingting Zhong, Xiaoqing Cheng, Yujuan Fu, Peng Xiao, Hongqiang Cheng, Di Wang, Yuehai Ke, Zhinong Jiang, Xue Zhang

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Figure 3

Epithelial Gab1 deficiency enhances susceptibility to DSS-induced experimental colitis.

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Epithelial Gab1 deficiency enhances susceptibility to DSS-induced experi...
Gab1IEC-KO mice (A–F) or Gab1My-KO mice (G and H), as well as their littermates, were administrated with water or 3% DSS for 7 days to induce experimental colitis. (A) Body weight loss, diarrhea, and rectal bleeding were monitored daily with or without DSS treatment. n = 3, 3, 8, 9, for Gab1fl/fl + H2O group, Gab1IEC-KO + H2O group, Gab1fl/fl + DSS group, Gab1IEC-KO + DSS group, respectively. (B) Gross morphology images of the colon from Gab1fl/fl or Gab1IEC-KO mice, and colon length were measured on day 7. n = 3, 3, 8, 9, respectively. (C) Gross morphology images of the spleen from Gab1fl/fl or Gab1IEC-KO mice and spleen weight assessed on day 7. n = 3, 3, 8, 9, respectively. (D) Representative images of H&E-stained colons from Gab1IEC-KO mice and littermate controls, with histopathology analysis of colitis performed on day 7. Scale bars, 100 μm. n = 3, 3, 6, 6, respectively. (E) Representative periodic acid–Schiff (PAS) staining of colonic sections from Gab1IEC-KO mice and littermate controls. Scale bars, 100 μm. n = 3, 3, 6, 6, respectively. (F) Gab1fl/fl (n = 13) and Gab1IEC-KO (n = 8) mice were challenged with 4% DSS for 7 days, and the survival of mice was monitored. (G) Gross morphology images of colons and colon length of Gab1fl/fl and Gab1My-KO mice. n = 3, 3, 9, 9, respectively. (H) Representative H&E staining and histopathological scores of colonic sections from Gab1My-KO mice, as well as littermate controls. Scale bars, 100 μm. n = 3, 3, 9, 9, respectively. Quantitative data were shown as mean ± SEM and are representative of 3 independent experiments. Statistical significance was assessed by using 2-way ANOVA with multiple comparisons test (A–D, G, and H) and log-rank test (F); *P < 0.05, **P < 0.01, ***P < 0.001.