Shun Wang 1, Weiqi Liu 1, Fuhua Gu 1, Jian Wang 1, Yuquan Guo 1, Liyang Guo 1, Yifan Li 1, Kexin Wang 1, Jie Zhang 1, Yecheng Yao 1, Zhiyong Wu 2, Jichang Li 3

DOI: 10.1016/j.redox.2026.104316

https://www.sciencedirect.com/science/article/pii/S2213231726003150?via%3Dihub

Abstract

Neutrophil extracellular trap (NET) formation is controlled by redox signaling and mitochondrial stress, but the connection between pathogen-induced Ca2+ influx, mitochondrial remodeling, and PAD-associated chromatin execution remains insufficiently defined. Using Mycoplasma gallisepticum (MG) as a model of respiratory mycoplasma infection, we examined how pathogen-activated redox signaling modulates NET formation and the subsequent fate of extracellular DNA. In neutrophils, MG promoted NET formation, although visible trap deposition was partly obscured by MG-associated nuclease activity. Early proteomic analysis indicated enrichment of calcium signaling, ROS-related pathways, autophagy/mitophagy, lysosome/phagosome programs, and MAPK-linked responses. Mechanistically, MG-induced NETosis was mediated through involved a Ca2+/ROS-associated program, in which mitochondrial dysfunction and mitophagy-related remodeling facilitated PAD3 nuclear redistribution, histone citrullination, and extracellular DNA release. In agreement with a supportive rather than exclusive function, mitophagy activation enhanced NET-associated responses, whereas mitophagy inhibition weakened but did not completely prevent MG-induced NET release. MG-associated nuclease activity digested extracellular traps, enabled MG to acquire DNA signals derived from digested trap structures, and lowered NET-dependent inflammatory activation in recipient macrophages and epithelial cells. In vivo, MG infection caused local NET-related responses and systemic neutrophil priming, linked to mainly associated with ROS/MAPK activation rather than prolonged mitophagy-related alterations. MG–Escherichia coli co-infection intensified inflammatory pathology, whereas DNase I produced partial protection. These results support a context-dependent model in which MG stimulates Ca2+-dependent redox signaling and mitochondrial remodeling, thereby contributing to PAD-associated NETosis, while pathogen nuclease activity modifies extracellular NET DNA fate and downstream inflammatory pathology.

Graphical abstract

Flow chart and proposed model of MG-induced NETosis and extracellular NET DNA remodeling. Image created by Figdraw (ID: IWOIA088c4 and YSYOT88c8c).