Smart Liposomal Nanocarrier Enhanced the Treatment of Ischemic Stroke through Neutrophil Extracellular Traps and Cyclic Guanosine Monophosphate-Adenosine Monophosphate Synthase-Stimulator of Interferon Genes (cGAS-STING) Pathway Inhibition of Ischemic Penumbra

Brain inflammation is regarded as one of the leading causes that aggravates secondary brain injury and hinders the prognosis of ischemic stroke. After ischemic stroke, high quantities of peripheral neutrophils are recruited to brain lesions and release neutrophil extracellular traps (NETs), leading to the aggravation of blood–brain barrier (BBB) damage, activation of microglia, and ultimate neuronal death. Herein, a smart multifunctional delivery system has been developed to regulate immune disorders in the ischemic brain. Briefly, Cl-amidine, an inhibitor of peptidylarginine deiminase 4 (PAD4), is encapsulated into self-assembled liposomal nanocarriers (C-Lipo/CA) that are modified by reactive oxygen species (ROS)-responsive polymers and fibrin-binding peptide to achieve targeting ischemic lesions and stimuli-responsive release of a drug. In the mouse model of cerebral artery occlusion/reperfusion (MCAO), C-Lipo/CA can suppress the NETs release process (NETosis) and further inhibit the cyclic guanosine monophosphate-adenosine monophosphate synthase-stimulator of interferon genes (cGAS-STING) pathway in an ischemic brain. In addition, MCAO mice treated with C-Lipo/CA significantly mitigated ischemic and reperfusion injury, with a reduction in the area of cerebral infarction to 12.1%, compared with the saline group of about 46.7%. These results demonstrated that C-Lipo/CA, which integrated microglia regulation, BBB protection, and neuron survival, exerts a potential therapy strategy to maximize ameliorating the mortality of ischemic stroke.