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 model was used to detect neutrophil migration, neutrophil extracellular traps level, and organ damage. Result: The PD-L1 siRNA-loaded LNPs that target neutrophils suppressed inflammation, reduced the release of neutrophil extracellular traps, 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 multiorgan damage and lethality resulting from cecal ligation and puncture. 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.