Epigenetic Regulation of the NET Formation–Blood–Brain Barrier Axis in Ischemic Stroke: Mechanisms, Therapeutic Targets and Translational Perspectives

Ischemic stroke elicits a rapid and sustained innate immune response that critically contributes to blood–brain barrier (BBB) breakdown and secondary neuronal injury. Among the cellular mediators involved, neutrophil extracellular traps (NETs) have emerged as potent effectors of neurovascular damage. However, the regulatory mechanisms governing NET formation and their prolonged impact on BBB integrity remain incompletely understood. Increasing evidence indicates that NET formation is an epigenetically regulated process, requiring chromatin remodeling, histone modifications, DNA methylation changes and non-coding RNA-mediated control within neutrophils under ischemic conditions. These epigenetic events license the extrusion of DNA–histone–enzyme complexes that directly injure endothelial cells, degrade tight junction proteins, activate innate immune signaling pathways and amplify neuroinflammatory cascades at the neurovascular unit. Moreover, NET-derived chromatin and associated mediators can induce transcriptional and epigenetic alterations in BBB cells, thereby sustaining barrier permeability and impairing vascular repair mechanisms. In this review, we synthesize current knowledge on the epigenetic regulation of NET formation and delineate how epigenetically regulated NETs function as key disruptors of BBB integrity in ischemic stroke. Understanding this NETosis–epigenetics–BBB axis may uncover novel therapeutic strategies aimed at preserving neurovascular integrity and limiting post-stroke brain injury.