Oxymatrine regulates microglia to produce IFN-β by activating the STING/TBK1/IRF3 pathway against experimental...

Oxymatrine is an alkaloid with the property of immunomodulation. Recent studies have demonstrated that oxymatrine inhibits experimental autoimmune encephalomyelitis (EAE), an animal model of multiple sclerosis (MS), by promoting the production of interferon-β (IFN-β). However, the mechanism through which oxymatrine regulates the production of IFN-β remains unclear. The aim of this study was to investigate the pharmacological effects and related molecular mechanisms of oxymatrine in the treatment of EAE through in vivo and in vitro experiments. Oxymatrine alleviated neurological dysfunction, demyelination, and inflammation in EAE mice. It reduced microglia/macrophage infiltration and polarization, lowered pro-inflammatory cytokine levels (iNOS, TNF-α), and enhanced the expression of IL-10 and IL-27. Additionally, oxymatrine upregulated the STING/TBK1/IRF3 signaling pathway in EAE mice, promoting IFN-β production by microglia. Similarly, in LPS-induced BV2 cells, oxymatrine suppressed inflammatory factors and activated the STING/TBK1/IRF3 pathway to enhance IFN-β production. Notably, treatment with the STING inhibitor, C176, reversed these effects in both EAE mice and LPS-induced BV2 cells, confirming the pathway's critical role in the mechanism of oxymatrine therapy. Oxymatrine promotes IFN-β production in microglia by upregulating the STING/TBK1/IRF3 signaling pathway, thereby alleviating the neurological dysfunction of EAE and reducing pathological and inflammatory events. This study identifies a novel anti-EAE mechanism of oxymatrine: promoting IFN-β production in microglia by activating the STING/TBK1/IRF3 pathway. However, it lacks clinical sample verification. If validated later, oxymatrine may provide a more economical, convenient endogenous IFN-β induction regimen for MS patients.