mRNA-Laden Lipid-Nanoparticle-Enabled in Situ CAR-Macrophage Engineering for the Eradication of Multidrug-Resistant Bacteria in a Sepsis Mouse Model

Abstract

Sepsis, which is the most severe clinical manifestation of acute infection and has a mortality rate higher than that of cancer, represents a significant global public health burden. Persistent methicillin-resistant Staphylococcus aureus (MRSA) infection and further host immune paralysis are the leading causes of sepsisassociated death, but limited clinical interventions that target sepsis have failed to effectively restore immune homeostasis to enable complete eradication of MRSA. To restimulate anti-MRSA innate immunity, we developed CRV peptide-modified lipid nanoparticles (CRV/LNP-RNAs) for transient in situ programming of macrophages (MΦs). The CRV/LNP-RNAs enabled the delivery of MRSA-targeted chimeric antigen receptor (CAR) mRNA (SasA-CAR mRNA) and CASP11 (a key MRSA intracellular evasion target) siRNA to MΦs in situ, yielding CAR-MΦs with boosted bactericidal potency. Specifically, our results demonstrated that the engineered MΦs could efficiently phagocytose and digest MRSA intracellularly, preventing immune evasion by the "superbug" MRSA. Our findings highlight the potential of nanoparticle-enabled in vivo generation of CAR-MΦs as a therapeutic platform for multidrug-resistant (MDR) bacterial infections and should be confirmed in clinical trials.

Synergically enhanced anti-tumor immunity ofin vivoCAR by circRNA vaccine boosting

“…Recently, in vivo delivery of CAR-encoding mRNAs to T cells or macrophages has been used to produce in vivo CAR-T or CAR-macrophage 7-11 . This innovative approach has shown efficacy in treating hematologic malignancies and myocarditis in mouse models, offering an off-the-shelf immunotherapy strategy with immense potential for therapeutic applications [7][8][9][10][11] . The use of mRNA technology addresses the safety concern of genomic integration and enables broader and more accessible application of CAR-T therapy in diverse clinical scenarios.Unlike the linear conformation of mRNA, circular RNAs (circRNAs) are covalently closed circular RNA molecules that are more stable than linear mRNAs in mammalian cells [12][13][14] .…”