Artesunate attenuates rheumatoid arthritis by inducing ferroptosis through the JAK1/STAT3 pathway

Rheumatoid arthritis (RA) is a chronic autoimmune disease primarily mediated by the abnormal proliferation and activation of fibroblast-like synoviocytes (SFs); this process is closely associated with ferroptosis. Previous studies have confirmed the therapeutic potential of artesunate (ART), a derivative of artemisinin, in alleviating RA. In this study, we further clarified that ART suppresses the abnormal activation of SFs and ameliorates RA progression through the JAK1/STAT3-GPX4-ferroptosis signaling pathway. First, we conducted a series of in vitro assays to evaluate the biological effects of ART on RASFs and osteoarthritis (OA) SFs, including cell proliferation, invasion and migration. Subsequently, we investigated the impact of ART on cell death, especially on ferroptosis-related indicators, including transmission electron microscopy (TEM), GPX4 expression, intracellular lipid peroxides, glutathione (GSH) and reactive oxygen species (ROS). To elucidate the underlying mechanism, we performed RNA sequencing to analyze differentially enriched signaling pathways and employed molecular docking to predict potential protein targets. Key findings were validated by Western blotting and ChIP-qPCR. Next, we established a collagen-induced arthritis (CIA) mouse model to compare arthritis symptoms, pathological changes, and immunological responses between ART-treated and control groups. Finally, we isolated primary synovial fibroblasts (CIA SFs) from synovial tissue to confirm ART’s effects and its molecular mechanism of abnormal activation of SFs. ART was shown to inhibit cytokine secretion, cell proliferation, and migration while promoting ferroptosis (increased ROS, MDA and lipid hydroperoxides, decreased GSH and GPX4). Notably, the suppressive effects of ART on cellular activation—including cytokine release, proliferation, and migration—were significantly reversed upon inhibition of ferroptosis. Mechanistically, ART downregulated GPX4 expression through suppression of the JAK1/STAT3 signaling pathway. In vivo experiments further demonstrated that ART ameliorated arthritis severity in CIA mice, as evidenced by reduced arthritis scores, joint swelling, as well as improved histopathological parameters and decreased cytokine levels in joint supernatants and serum. Part of this therapeutic effect may be attributed to the induction of ferroptosis in SFs within CIA joints. In conclusion, our study provided the evidence that ART inhibits the activation of SFs by inducing ferroptosis through the JAK1/STAT3-GPX4 signaling pathway, thereby attenuating joint damage. In RASFs, ART inhibits cell activation (cytokine secretion, cell proliferation and migration). In RASFs, ART inhibits cell activation by inducing ferroptosis through the JAK1/STAT3 signaling pathway. In animal models, ART attenuates collagen-induced arthritis by inducing the ferroptosis of CIA SFs.