Spatiotemporal synergistic drug co-delivery via a dual-crosslinked liposomal platform for potent NETs blockade in rheumatoid arthritis.

Neutrophil extracellular traps (NETs) are key drivers of autoimmune pathology and inflammatory cascades in rheumatoid arthritis (RA). NETs formation is jointly fueled by reactive oxygen species (ROS) burst and PAD4-mediated chromatin decondensation, suggesting that simultaneous blockade of both events represents a multi-pronged therapeutic strategy that single pathway inhibitors cannot achieve. However, multi-agents delivery systems often suffer from inconsistent in vivo behavior of the drugs, which undermines cooperative efficacy. Herein, we developed a PGP-modified, lipid bilayer-crosslinked and nanogel-embedded liposomal platform (PLipoGel@CH) for effective co-delivering chlorogenic acid (CA, a ROS scavenger) and hydroxychloroquine (HCQ, a PAD4 inhibitor) to activated neutrophils. This dual-protection architecture effectively overcame the limitations of conventional nanocarriers by preventing drug leakage and ensuring synchronized in vivo performance of the two drugs, thereby maximizing their spatiotemporal synergistic anti-NETs efficacy. PLipoGel@CH achieved superior neutrophil-specific targeting via PGP peptide. In activated neutrophils, the combination therapy synergistically suppressed NETs by 73% and markedly inhibited the subsequent inflammatory cascade. Notably, when both drugs were co-loaded in PLipoGel@CH, HCQ significantly delayed intracellular CA clearance by inhibiting lysosomal acidification and P-glycoprotein-mediated efflux. Moreover, HCQ further suppressed the hepatic enzyme UGT1A1, thus extending the in vivo half-life of CA by 3-fold and increasing its bioavailability by 15-fold. After intravenous injection, PLipoGel@CH leveraged the inflammatory tropism of neutrophils to accumulate in inflamed joints, and significantly attenuated inflammatory responses and histopathological damage by blocking NETs formation. By harmonizing the in vivo performance of synergistic agents, this spatiotemporal synergistic nanoplatform provides a potent strategy for RA treatment.