Flavonoids From Sophora tonkinensis Disrupt STING ‐ TBK 1‐ IRF 3 Complex Assembly and Ameliorate Inflammatory Diseases by Modulating c GAS ‐ STING Signaling

cGAS-STING pathway is a core regulator of innate immunity and inflammatory responses. Aberrant activation of the cGAS-STING pathway is closely associated with the progression of multiple inflammatory disorders. Flavonoids from Sophora tonkinensis (STF) are the main ingredients of this traditional Chinese medicine with definite anti-inflammatory activity, whereas its molecular mechanism against inflammation remains unclear. This work aimed to explore the regulatory effect and underlying molecular mechanism of STF on the cGAS-STING pathway, and verify its therapeutic efficacy on typical inflammatory diseases in vivo. BMDMs and human THP-1 were used for in vitro experiments. Western blot, RT-qPCR, ELISA, Co-IP, and Native-PAGE were performed to detect protein phosphorylation, gene expression, protein-protein interaction, and STING oligomerization. Lipopolysaccharide/D-galactosamine (LPS/D-GalN)-induced acute liver injury and LPS-induced sepsis mouse models were established to evaluate the in vivo anti-inflammatory and organ-protective effects of STF. Serum biochemical detection and gene expression analysis were carried out for in vivo sample evaluation. STF suppressed ISD-triggered activation of the cGAS-STING pathway, as evidenced by reduced phosphorylation of interferon regulatory factor 3 (IRF3) and STING, as well as decreased expression of downstream inflammatory mediators. Mechanistically, STF did not interfere with STING oligomerization but blocked the assembly of the STING-TBK1 complex and the interaction between IRF3 and TBK1. In vivo experiments demonstrated that STF dose-dependently alleviated hepatic pathological damage and hepatocyte apoptosis in a mouse model of acute liver injury. Furthermore, STF improved survival rates and attenuated multi-organ injury in septic mice by reducing the release of pro-inflammatory cytokines. STF exerts targeted anti-inflammatory activity via disrupting STING-TBK1 and TBK1-IRF3 complex assembly and inhibiting the cGAS-STING signaling cascade. It provides experimental evidence for the clinical application and translational research of Sophora tonkinensis and its flavonoid components in the treatment of cGAS-STING-related inflammatory diseases.