A Nitric Oxide-Inhibitory Ionizable Guanidine Lipid for Anti-Inflammatory mRNA Delivery in Acute Lung Injury
Abstract
Lipid nanoparticles (LNPs) represent the most clinically advanced platform for mRNA delivery, yet their inherent immunogenicity remains a critical barrier to therapeutic efficacy. Nitric oxide (NO) is a central effector in macrophage-driven inflammation, making it a particularly compelling molecular target for the design of anti-inflammatory LNP. Here, we screened a library of ionizable guanidine compounds and identified G9, a potent inhibitor that suppresses NO production in peritoneal M1 macrophages and reprograms macrophages toward an anti-inflammatory phenotype. Derivatization of G9 yielded G9-1, a guanidine-based ionizable lipid with an intrinsic NO-inhibitory motif, which retains full anti-inflammatory activity while enabling efficient mRNA encapsulation and preferential delivery to lung-resident cells. In a murine acute lung injury (ALI) model, G9-1 LNPs loaded with IL-10 mRNA exerted synergistic therapeutic effects, reducing inflammatory cell infiltration, suppressing pro-inflammatory cytokines and improving systemic markers of tissue injury. This work establishes NO inhibition as a design principle for anti-inflammatory ionizable lipids and introduces a new class of LNP with intrinsic immunomodulatory activity for safer mRNA therapeutics in inflammatory disorders.
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