1. Inhibition of Efferocytosis by Extracellular CIRP–Induced Neutrophil Extracellular Traps.
- Author
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Kehong Chen, Atsushi Murao, Arif, Adnan, Satoshi Takizawa, Hui Jin, Jianxin Jiang, Monowar Aziz, and Ping Wang
- Subjects
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LEUCOCYTE elastase , *NEUTROPHILS , *RNA-binding proteins , *PERITONEUM , *THYMOCYTES - Abstract
Phagocytic clearance of apoptotic cells by the macrophages (efferocytosis) is impaired in sepsis, but its mechanism is poorly understood. Extracellular cold-inducible RNA-binding protein (eCIRP) is a novel damage-associated molecular pattern that fuels inflammation. We identify that eCIRP-induced neutrophil extracellular traps (NETs) impair efferocytosis through a novel mechanism. Coculture of macrophages and apoptotic thymocytes in the presence of recombinant murine CIRP (rmCIRP)–induced NETs significantly inhibited efferocytosis. Efferocytosis was significantly inhibited in the presence of rmCIRP-treated wild-type (WT), but not PAD4-/- neutrophils. Efferocytosis in the peritoneal cavity of rmCIRP-injected PAD4-/-mice was higher than WT mice. Milk fat globule–EGF–factor VIII (MFG-E8), an opsonin, increased macrophage efferocytosis, whereas the inhibition of efferocytosis by NETs was not rescued upon addition of MFG-E8, indicating disruption of MFG-E8’s receptor(s) αvβ3 or αvβ5 integrin by the NETs. We identified neutrophil elastase in the NETs significantly inhibited efferocytosis by cleaving macrophage surface integrins αvβ3 and αvβ5. Using a preclinical model of sepsis, we found that CIRP-/- mice exhibited significantly increased rate of efferocytosis in the peritoneal cavity compared with WT mice. We discovered a novel role of eCIRP-induced NETs to inhibit efferocytosis by the neutrophil elastase–dependent decrease of αvβ3/αvβ5 integrins in macrophages. Targeting eCIRP ameliorates sepsis by enhancing efferocytosis. [ABSTRACT FROM AUTHOR]
- Published
- 2021
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