Artificial mesenchymal stem cell extracellular vesicles enhanced ischemic stroke treatment through targeted remodeling brain microvascular endothelial cells

Ischemic stroke is the leading cause of disability and mortality worldwide. The blood-brain barrier (BBB) is the first line of defense after ischemic stroke. Disruption of the BBB induced by brain microvascular endothelial cells (BMECs) dysfunction is a key event that triggers secondary damage to the central nervous system, where blood-borne fluids and immune cells penetrate the brain parenchyma, causing cerebral edema and inflammatory response and further aggravating brain damage. Here, we develop a novel artificial mesenchymal stem cell (MSC) extracellular vesicles by integrating MSC membrane proteins into liposomal bilayers, which encapsulated miR-132-3p with protective effects on BMECs. The artificial extracellular vesicles (MSCo/miR-132-3p) had low immunogenicity to reduce non-specific clearance by the mononuclear phagocytosis system (MPS) and could target ischemia-injured BMECs. After internalization into the damaged BMECs, MSCo/miR-132-3p escaped the lysosomes via the H_II phase transition of 1,2-dioleoyl-sn-glycero-3-phosphoethanolamine (DOPE) and decreased cellular reactive oxygen species (ROS) and apoptosis levels by regulating the RASA1/RAS/PI3K/AKT signaling pathway. In the transient middle cerebral artery occlusion (tMCAO) models, MSCo/miR-132-3p targeted impaired brain regions (approximately 9 times the accumulation of plain liposomes at 12 h), reduced cerebral vascular disruption, protected BBB integrity, and decreased infarct volume (from 44.95% to 6.99%).