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

ABSTRACT 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.