A novel function of RHOA as a host-dependent factor in Glaesserella parasuis infection of LLC-PK1 cells

Glaesserella parasuis ( G. parasuis ), a lethal pathogen causing Glässer’s disease, poses severe threats to global swine health. While the small GTPase Ras homolog gene family member A ( RHOA ) is implicated in viral pathogenesis, its role in bacterial infections remains unexplored. Here, we established an in vitro infection model using porcine LLC-PK1 cells and demonstrated that G. parasuis induces adhesion and pseudopodia-mediated invasion, resulting in approximately 99% cell death within 120 h post-infection. Crucially, RHOA expression was upregulated during infection, and RHOA knockout reduced bacterial adhesion and invasion, rescuing cell viability to 77.30%. Transcriptomic profiling of RHOA -knockout cells revealed 1797 differentially expressed genes, revealing indirect effects on cytoskeleton remodeling ( ACTG1 / MYL7/MYL9 downregulation) and tight junction stabilization ( CDH1 / CLDN1/CDH5 upregulation). This establishes RHOA as a key host factor facilitating G. parasuis infection, providing targets for disease control.