HUWE1 mediates inflammasome activation and promotes host defense against bacterial infection
Yu Guo, … , Genze Shao, Xiaopeng Qi
Yu Guo, … , Genze Shao, Xiaopeng Qi
Published October 26, 2020
Citation Information: J Clin Invest. 2020;130(12):6301-6316. https://doi.org/10.1172/JCI138234.
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Research Article Immunology Inflammation

HUWE1 mediates inflammasome activation and promotes host defense against bacterial infection

Abstract

The mechanism by which inflammasome activation is modulated remains unclear. In this study, we identified an AIM2-interacting protein, the E3 ubiquitin ligase HUWE1, which was also found to interact with NLRP3 and NLRC4 through the HIN domain of AIM2 and the NACHT domains of NLRP3 and NLRC4. The BH3 domain of HUWE1 was important for its interaction with NLRP3, AIM2, and NLRC4. Caspase-1 maturation, IL-1β release, and pyroptosis were reduced in Huwe1-deficient bone marrow–derived macrophages (BMDMs) compared with WT BMDMs in response to stimuli to induce NLRP3, NLRC4, and AIM2 inflammasome activation. Furthermore, the activation of NLRP3, NLRC4, and AIM2 inflammasomes in both mouse and human cells was remarkably reduced by treatment with the HUWE1 inhibitor BI8622. HUWE1 mediated the K27-linked polyubiquitination of AIM2, NLRP3, and NLRC4, which led to inflammasome assembly, ASC speck formation, and sustained caspase-1 activation. Huwe1-deficient mice had an increased bacterial burden and decreased caspase-1 activation and IL-1β production upon Salmonella, Francisella, or Acinetobacter baumannii infection. Our study provides insights into the mechanisms of inflammasome activation as well as a potential therapeutic target against bacterial infection.

Authors

Yu Guo, Longjun Li, Tao Xu, Xiaomin Guo, Chaoming Wang, Yihui Li, Yanan Yang, Dong Yang, Bin Sun, Xudong Zhao, Genze Shao, Xiaopeng Qi

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Figure 9

HUWE1 deficiency increases host susceptibility to Salmonella, F. novicida, and A. baumannii infection.

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HUWE1 deficiency increases host susceptibility to Salmonella, F. novicid...
Huwe1fl/fl-CreER and Huwe1+/+-CreER mice were injected with tamoxifen (2 mg/100 μL per mouse) for 5 consecutive days. Five days after the last injection, mice were infected with bacterial pathogens, and the bacterial burden and host immune responses were analyzed. (A and B) Tamoxifen-treated Huwe1fl/fl-CreER and Huwe1+/+-CreER mice were infected intraperitoneally with 5000 CFU Salmonella, and body weight change after infection (A) and bacterial burden in the spleen and liver on day 2 after infection (B) were measured. (C and D) Tamoxifen-treated Huwe1fl/fl-CreER and Huwe1+/+-CreER mice were infected subcutaneously with 1.5 × 105 CFU F. novicida, and (C) body weight change after infection and (D) bacterial burden in the spleen and liver on day 2 after infection were measured. (E) H&E staining of liver sections from uninfected and Salmonella- or F. novicida–infected mice in B and D. Dashed outlines indicate infiltrated immune cells. Scale bars: 100 μm. (F) Tamoxifen-treated Huwe1fl/fl-CreER and Huwe1+/+-CreER mice were infected intranasally with 5.0 × 108 CFU A. baumannii, and bacterial burden in the lungs on day 1 after infection was measured. (G) H&E staining of lung sections from uninfected and A. baumannii–infected mice in F. Scale bars: 100 μm. (H and I) Immunoblot analysis of pro–caspase-1 and its subunit p20 in the liver, spleen, and lungs of uninfected, Salmonella-infected (H), F. novicida–infected, and A. baumannii–infected (I) mice. GAPDH was used as a loading control. (J) ELISA analysis of IL-1β, TNF, and IL-6 in sera from uninfected and bacteria-infected mice in B, D, and F. Each dot represents an individual mouse (B, D, F, and J). *P < 0.05, **P < 0.01, ***P < 0.001, and ****P < 0.0001, by 2-sided Student’s t test without multiple-comparisons correction. Data are representative of 2 independent experiments.