The delivery of PD-L1 siRNA by neutrophil-targeted lipid nanoparticles effectively ameliorates sepsis

Abstract Background Sepsis, a complex and life-threatening disease, poses a significant global burden affecting over 48 million individuals. Recently, it has been reported that programmed death-ligand 1 (PD-L1) expressed on neutrophils is involved in both inflammatory organ dysfunction and immunoparalysis in sepsis. However, there is a dearth of strategies to specifically target PD-L1 in neutrophils in vivo . Methods We successfully developed two lipid nanoparticles (LNPs) specifically targeting neutrophils by delivering PD-L1 siRNA via neutrophil-specific antibodies and polypeptides. In vivo and in vitro experiments were performed to detect lipid nanoparticles into neutrophils. A mouse cecal ligation and puncture (CLP) model was used to detect neutrophil migration, neutrophil extracellular traps (NETs) level, and organ damage. Result The PD-L1 siRNA-loaded LNPs that target neutrophils suppressed inflammation, reduced the release of NETs, and inhibited T-lymphocyte apoptosis. This approach could help maintain homeostasis of both the immune and inflammatory responses during sepsis. Furthermore, the PD-L1 siRNA-loaded LNPs targeting neutrophils have the potential to ameliorate the multi-organ damage and lethality resulting from CLP. Conclusions Taken together, our data identify a previously unknown drug delivery strategy targeting neutrophils, which represents a novel, safe, and effective approach to sepsis therapy.