Vibrio vulnificus outer membrane vesicles induce mitochondrial dysfunction in macrophages via the TNF signaling pathway.

Vibrio vulnificus (V. vulnificus) is a highly virulent zoonotic pathogen causing severe septicemia and tissue necrosis in humans, characterized by a cytokine storm. While bacterial outer membrane vesicles (OMVs) are known to mediate host-pathogen interactions, their specific contribution to V. vulnificus-induced immunopathology remains obscure. In this study, we isolated and characterized V. vulnificus-derived OMVs and investigated their impact on murine macrophages (J774A.1). We demonstrate that these OMVs are actively internalized by macrophages in a time-dependent manner, triggering a robust pro-inflammatory response. Transcriptomic analysis and subsequent validation revealed that internalized OMVs activated the TNF signaling pathway, leading to the phosphorylation of NF-κB and MAPK (p38/JNK) cascades. Crucially, OMV exposure induced severe mitochondrial dysfunction, evidenced by ultrastructural disruption and a significant reduction in mitochondrial membrane potential. Notably, pharmacological blockade of the TNF receptor with the antagonist R-7050 effectively attenuated this mitochondrial damage. These findings establish a novel pathogenic mechanism wherein V. vulnificus OMVs exploit the host TNF signaling axis to drive mitochondrial injury, providing new insights into the cellular mechanisms of V. vulnificus lethality and suggesting the TNF-mitochondria axis as a potential therapeutic target.