Activation of the cGAS-STING Pathway by NETs Promotes Inflammatory Injury in Myocardial Ischemia-Reperfusion

Myocardial ischemia-reperfusion injury (MIRI) is a major complication of reperfusion therapy, driven by excessive sterile inflammation. During this process, neutrophils release abundant neutrophil extracellular traps (NETs), which exacerbate tissue damage, yet the underlying molecular mechanisms remain incompletely understood.

This study tested the hypothesis that NETs activate the cGAS-STING pathway via their double-stranded DNA (dsDNA) skeleton, thereby driving inflammatory injury in MIRI.

A rat MIRI model (30-min ischemia/2-h reperfusion) and H9c2 cardiomyocyte hypoxia/reoxygenation (H/R) model were employed. NETs were isolated from PMA-stimulated neutrophils. Pharmacological inhibitors (DNase I, RU.521, C-176), siRNA-mediated cGAS knockdown, and plasmid-mediated cGAS overexpression were used to interrogate pathway engagement. Evaluated endpoints included infarct size, myocardial enzymes, NETs markers, cGAS-STING pathway protein phosphorylation, inflammatory cytokines, and reactive oxygen species.

In MIRI rats, NETs markers and cGAS-STING activation were markedly elevated, while DNase I, RU.521, or C-176 significantly reduced infarct size and inflammatory responses. In vitro, NETs directly activated the cGAS-STING/TBK1/NF-κB axis in H/R-treated cardiomyocytes, promoting cytokine release and ROS production-effects abolished by DNase I or cGAS knockdown, but potentiated by cGAS overexpression.

NETs-derived dsDNA activates the cGAS-STING pathway in cardiomyocytes, driving downstream inflammatory responses that worsen MIRI. cGAS serves as a critical molecular node in this pathogenic axis, representing a promising therapeutic target for MIRI.