Targeted Delivery of cGAS Inhibitor Ru.521 to Macrophages Attenuates Immune Rejection Following Renal Transplantation

Ischemia–reperfusion injury (IRI) during renal transplantation triggers sterile inflammation and activates the cGAS–NF-κB/IRF3 axis, thereby promoting macrophage and T-cell–mediated rejection. However, systemic cGAS inhibition carries risks of off-target immunosuppression and infection. Here, we combined bulk and single-cell transcriptomic analyses (GSE157292, GSE268009, GSE257542) with in vivo models, including unilateral renal IRI in C57BL/6 mice and Wistar-to-Sprague Dawley rat orthotopic kidney transplantation, to define key cellular drivers and evaluate targeted cGAS inhibition. We engineered macrophage-membrane–camouflaged, S2P-functionalized PLGA nanoparticles loaded with the cGAS inhibitor Ru.521 (PLGA + Ru.521@MMS2P) and characterized their physicochemical properties, biodistribution, targeting, and biosafety. Transcriptomic and experimental validation identified M1 macrophages and CD8⁺ T cells as principal effectors with robust activation of the cGAS–NF-κB/IRF3 pathway and downstream chemokines. Free Ru.521 attenuated IRI-induced renal injury but caused pulmonary inflammation. In contrast, PLGA + Ru.521@MMS2P maintained favorable morphology, particle size, zeta potential, and sustained-release behavior, exhibited preferential uptake by M1 macrophages, and selectively accumulated in injured kidneys. In both mouse and rat models, PLGA + Ru.521@MMS2P significantly improved survival, renal function, histopathology, and tubular apoptosis compared with free Ru.521, while decreasing M1 macrophage and CD8⁺ T-cell infiltration and suppressing NF-κB/IRF3 signaling without detectable systemic toxicity. These findings demonstrate that macrophage membrane–coated, S2P-modified nanoparticles enable spatially restricted delivery of Ru.521 to pathogenic macrophages, effectively mitigating renal transplant IRI and immune rejection while minimizing off-target immune suppression, and provide a promising nanobiotechnology-based strategy for precise modulation of innate immune sensing in transplantation.