Multi-Omics and Functional Analysis of Salmonella ArtAB Toxin Activity Reveals Transcriptomic Remodeling and Epithelial Barrier Dysfunction

AB5 toxins are important virulence factors produced by Gram-negative bacteria and have been identified in many non-typhoidal Salmonella (NTS) serovars; however, their effects on host cell signaling and epithelial barrier function remain poorly understood. This study characterized the molecular and functional effects of purified ArtAB toxin and its binding subunit, ArtB, from multidrug-resistant Salmonella Typhimurium definitive type 104 (DT104). Equimolar concentrations of ArtAB (10 µg/mL) and ArtB (7.25 µg/mL) were evaluated in Chinese hamster ovary (CHO-K1) cells using cytotoxicity assays, quantitative proteomics, and mRNA sequencing, while barrier function was assessed in C2BBe1 human intestinal epithelial cells using electric cell-substrate impedance sensing (ECIS). In CHO-K1 cells, both proteins exhibited minimal cell death. ArtB elicited pronounced proteomic changes associated with endoplasmic reticulum (ER) homeostasis, vesicular trafficking, and lysosomal processing, but limited transcriptional responses. ArtAB instead altered host transcriptional programs associated with cell growth, inflammatory signaling, and cytoskeletal organization. Unlike ArtB, ArtAB significantly reduced barrier function in C2BBe1 cells. Together, these findings show that ArtAB remodels host cell signaling without overt cytotoxicity in CHO-K1 cells and produces a distinct functional effect in C2BBe1 cells. Although obtained in different cellular models, these results provide insight into the potential role of ArtAB in NTS pathogenesis.