Extracellular Vesicle–Mimetic Ghost Nanovesicles for Delivering Anti‐Inflammatory Drugs to Mitigate Gram‐Negative Bacterial Outer Membrane Vesicle–Induced Systemic Inflammatory Response Syndrome

Sepsis is one of the major causes of death in hospital patients and is represented by systemic inflammatory response syndrome (SIRS) associated with infection. Gram-negative bacteria including Escherichia coli can provoke sepsis by stimulating the immune systems. Outer membrane vesicles (OMVs), nanosized vesicular structures derived from Gram-negative bacteria, contain several pathogen-associated molecular patterns, and are demonstrated to mediate SIRS. Here, extracellular vesicle-mimetic ghost nanovesicles loaded with dexamethasone, an anti-inflammatory drug, are developed using alkaline solution, sonication, and buoyant density gradient ultracentrifugation. These ghost nanovesicles have comparable physical features with naturally released extracellular vesicles but have 200-fold higher production yields than extracellular vesicles. Importantly, these ghost nanovesicles are devoid of potentially unwanted luminal cargos, including cytosolic proteins and nucleic acids. By maintaining the same topology as the parental cells, these dexamethasone-loaded ghost nanovesicles derived from human U937 monocytes reduce the release of interleukin-8 from OMV-treated endothelial cells in vitro, and mitigate the symptoms of OMV-induced SIRS in vivo. This study sheds light on using extracellular vesicle-mimetic ghost nanovesicles to deliver therapeutics to treat diseases such as bacterial sepsis.