The responses of macrophages in interaction with neutrophils that undergo NETosis

作者：Daigo Nakazawa, Haruki Shida, Yoshihiro Kusunoki, Arina Miyoshi, Saori Nishio, Utano Tomaru, Tatsuya Atsumi, Akihiro Ishizu · 发表于：Journal of Autoimmunity · 年份：2015 · DOI：10.1016/j.jaut.2015.08.018 · 被引用次数：203 · 研究领域：Neutrophil, Myeloperoxidase and Oxidative Mechanisms、Immune cells in cancer、Inflammasome and immune disorders

Neutrophil extracellular traps (NETs) are net-like chromatin fibers decorated with antimicrobial proteins, which are released from dying neutrophils. The death of neutrophils with NET formation is called NETosis. Although NETs play important roles in the innate immunity, especially in the elimination of microbes, the extracellular release of DNA and intra-cytoplasmic/nuclear proteins can, on the other hand, result in diverse adversities to the hosts. Therefore, NETosis is adequately regulated in vivo. Currently, two mechanisms, namely DNase I-dependent digestion and phagocytosis by macrophages, have been shown as such regulatory mechanisms. In this study, we focused on the interaction of macrophages and neutrophils that underwent NETosis. Results demonstrated that macrophages displayed a phenotype-dependent response after degradation of NETs. Several hours after the interaction, M2 macrophages induced a pro-inflammatory response, while M1 macrophages underwent cell death with nuclear decondensation. This nuclear decondensation of M1 macrophages occurred in a peptidylarginine deiminase 4-dependent manner and resulted in a local release of extracellular DNA. Thereafter, M1 macrophages degraded DNA derived from themselves in a caspase-activated DNase-dependent manner resulting in the clearance of extracellular DNA within 24 h. This transient increase and subsequent clearance mechanism of extracellular DNA seems very reasonable in terms of the double-edged sword-like property of ...