VDAC1 mediates LPS-induced T cell inflammation via mtDNA release and cGAS-STING activation.

Sepsis, a life-threatening condition characterized by dysregulated immune responses, leads to high mortality and morbidity. While splenic T cells are pivotal in systemic inflammation, their underlying mechanisms remain elusive. Here, we investigated the impact of bacterial endotoxin lipopolysaccharide (LPS) on mouse spleen tissue and primary T cells. LPS challenge provoked splenic inflammation, as evidenced by elevated levels of TNF-α, IFN-γ, IL-6, and IL-18 in whole spleen tissue. Transcriptomic profiling of whole spleen tissue implicated the cytosolic DNA-sensing pathway. Mechanistic studies in purified primary splenic CD3+ T cells revealed that LPS triggered mitochondrial dysfunction, characterized by increased mitochondrial ROS (mtROS), Ca2+ mobilization, and mitochondrial DNA (mtDNA) release into the cytosol, concurrent with VDAC1 oligomerization. Mechanistically, VDAC1 oligomerization was essential for LPS-induced mtDNA release and subsequent activation of the cGAS-STING-TBK1 axis. Notably, the VDAC1 oligomerization inhibitor VBIT-12 reversed cGAS-STING activation and cytokine expression. Collectively, our findings unveil a novel pathway wherein LPS induces VDAC1 oligomerization, leading to mtDNA leakage and activation of the cGAS-STING-TBK1 pathway in T cells, thereby fueling inflammation. This mechanism not only deepens our understanding of T cell-mediated immunopathology in endotoxemia but also highlights VDAC1 and associated mitochondrial function as potential therapeutic targets for sepsis and related inflammatory diseases.