Induction of neutrophil extracellular traps during tissue injury: Involvement of STING and Toll‐like receptor 9 pathways

• Published in: Cell proliferation 2019-05, Vol.52 (3), p.e12579-n/a
• Main Authors: Liu, Li, Mao, Ye, Xu, Bocheng, Zhang, Xiangxian, Fang, Chunju, Ma, Yu, Men, Ke, Qi, Xiaorong, Yi, Tao, Wei, Yuquan, Wei, Xiawei
• Format: Article
• Language: English
• Subjects: AMP; Animals; Cyclic GMP; cyclic GMP‐AMP synthase; Deoxyribonucleic acid; DNA; DNA, Mitochondrial - metabolism; Elastase; Extracellular Traps - metabolism; Female; Gene expression; Humans; Identification methods; In Vitro Techniques; In vivo methods and tests; Inflammation; Inflammation - metabolism; Injuries; Leukocyte Elastase - metabolism; Leukocytes (neutrophilic); Lungs; Membrane Proteins - metabolism; Mice; Mice, Inbred C57BL; Microscopy, Fluorescence; Mitochondrial DNA; Models, Biological; Neutrophil Activation; neutrophil extracellular traps; Neutrophils; Neutrophils - metabolism; Nucleotidyltransferases - metabolism; Organic chemistry; Original; Oxidation-Reduction; Protein-arginine deiminase; Reactive oxygen species; Reactive Oxygen Species - metabolism; Tissues; TLR9 protein; Toll-Like Receptor 9 - metabolism; Toll-like receptors; Toll‐like receptor 9; Trauma; Viruses; Wounds and Injuries - metabolism
• ISSN: 0960-7722; 1365-2184
• DOI: 10.1111/cpr.12579

Objectives Neutrophils are thought to release neutrophil extracellular traps (NETs) to form in response to exogenous bacteria, viruses and other pathogens. However, the mechanisms underlying NET formation during sterile inflammation are still unclear. In this study, we would like to identify neutrophil extracellular traps formation during sterile inflammation and tissue injury and associated pathways and its mechanism. Materials and methods We identified different injuries such as chemical‐induced and trauma‐induced formation of NETs and investigated mechanism of the formation of NETs in vitro and in vivo during the treatment of mtDNA. Results Here, we find the release of mitochondrial DNA (mtDNA) and oxidized mtDNA in acute peripheral tissue trauma models or other chemically induced lung injury, and moreover, endogenous mtDNA and oxidized mtDNA induce the formation of NETs and sterile inflammation. Oxidized mtDNA is a more potent inducer of NETs. Mitochondrial DNA activates neutrophils via cyclic GMP‐AMP synthase (cGAS)‐STING and the Toll‐like receptor 9 (TLR9) pathways and increases the production of neutrophil elastase and extracellular neutrophil‐derived DNA in NETs. Mitochondrial DNA also increases the production of reactive oxygen species (ROS) and expression of the NET‐associated proteins Rac 2 and peptidylarginine deiminase 4 (PAD4). Conclusions Altogether, these findings highlight that endogenous mitochondrial DNA inducted NETs formation and subsequent sterile inflammation and the mechanism associated with NET formation.