Engineered Bacterial Nanosyringes Induce Transient and Controllable Hepatic Immune-Metabolic Responses

The photorhabdus virulence cassette (PVC), a programmable protein-delivery nanodevice derived from bacterial contractile injection systems, can be engineered to possess recognizing and targeting human cells. However, whether it impacts mammalian liver function and transcriptional networks remains largely unknown. Engineered PVCs were injected intraperitoneally into BALB/c mice. Hepatic transcriptomes were analyzed by RNA sequencing (RNA-seq) and Gene Ontology/Kyoto Encyclopedia of Genes and Genomes (GO/KEGG) clustering was applied to differentially expressed genes (DEGs) in RNA-seq analysis of the liver's transcriptomes. No acute hepatotoxicity was seen, as indicated by unchanged plasma alanine transaminase (ALT) and aspartate aminotransferase (AST). RNA-seq identified 6,471 DEGs compared with the 0 h group, early transcriptional responses in (2-4 h) group were dominated by innate immune pathways (NF-κB, TNF, and chemokine), driven by upregulation of pattern-recognition receptors (e.g. Tlr2, Myd88, and Cd14) and cytokines. In 12-24 h group, analysis of the significantly downregulated genes showed that multiple genes, such as CYP450, glutathione S-transferases, and carboxylesterase family genes were markedly decreased at 12 h, most of the genes gradually approached 0 h. Time-series analysis revealed coordinated immune-metabolic dynamics: acute inflammation (bell-shaped trend) followed by metabolic reprogramming (U-shaped trend). Single intraperitoneal injection of PVC induces a transient and controllable immune-metabolic response without obvious hepatotoxicity.