The orphan receptor Nur77 binds cytoplasmic LPS to activate the non-canonical NLRP3 inflammasome
- Immunity. 2023 Apr 11;56(4):753-767.e8. doi: 10.1016/j.immuni.2023.03.003.
- 1. Department of Immunology, School of Basic Medical Sciences, Peking University, Beijing 100191, China; NHC Key Laboratory of Medical Immunology, Peking University, Beijing 100191, China; Key Laboratory of Molecular Immunology, Chinese Academy of Medical Sciences, Beijing 100191, China.
- 2. Department of Anesthesiology, Peking University Third Hospital, Beijing 100191, China.
- 3. Department of Sports Medicine, Peking University Third Hospital, Beijing 100191, China; Beijing Key Laboratory of Sports Injuries, Institute of Sports Medicine of Peking University, Beijing 100191, China.
- 4. CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China. Electronic address: [email protected].
- 5. Department of Immunology, School of Basic Medical Sciences, Peking University, Beijing 100191, China; NHC Key Laboratory of Medical Immunology, Peking University, Beijing 100191, China; Key Laboratory of Molecular Immunology, Chinese Academy of Medical Sciences, Beijing 100191, China. Electronic address: [email protected].
Intracellular sensing of lipopolysaccharide (LPS) by murine caspase-11 or human caspase-4 initiates a protease cascade, termed the non-canonical inflammasome, that results in gasdermin D (GSDMD) processing and subsequent NLRP3 inflammasome activation. In an effort aimed at identifying additional sensors for intracellular LPS by biochemical screening, we identified the nuclear Orphan Receptor Nur77 as an LPS-binding protein in macrophage lysates. Nr4a1-/- macrophages exhibited impaired activation of the NLRP3 inflammasome, but not caspase-11, in response to LPS. Biochemical mapping revealed that Nur77 bound LPS directly through a domain in its C terminus. Yeast two-hybrid assays identified NLRP3 as a binding partner for Nur77. The association between Nur77 and NLRP3 required the presence of LPS and dsDNA. The source of dsDNA was the mitochondria, requiring the formation of gasdermin-D pores. In vivo, Nur77 deficiency ameliorated host response to endotoxins. Thus, Nur77 functions as an intracellular LPS sensor, binding mitochondrial DNA and LPS to activate the non-canonical NLRP3 inflammasome.