Exploring endothelial dysfunction in SLE: cGAS-STING-IRF3 pathway activation by dsDNA

<b>Background</b>: Systemic lupus erythematosus (SLE) is an autoimmune disease often associated with anti-double stranded DNA (anti-dsDNA) antibodies and endothelial dysfunction, yet the mechanisms linking extracellular DNA to vascular injury remain unclear.<b>Methods</b>: We collected clinical samples from SLE patients and healthy controls, cultured human umbilical vein endothelial cells (HUVECs), and applied cell viability assays, ELISA, RT-qPCR, and Western blot to assess endothelial injury and activation pathways. We measured levels of von Willebrand factor (vWF), soluble thrombomodulin (sTM), and E-selectin in patient sera and cell culture supernatants.<b>Results</b>: SLE patients, particularly those positive for anti-dsDNA antibodies, showed significantly higher serum vWF, sTM, and E-selectin compared to controls (P < 0.05). In vitro, exposure of HUVECs to dsDNA induced a dose- and time-dependent reduction in cell viability, with an IC50 of 2.874 μg/ml, and significantly upregulated vWF, sTM, and E-selectin secretion. Mechanistically, dsDNA treatment activated the cGAS-STING-IRF3 signaling pathway, evidenced by increased mRNA and protein expression of cGAS, STING, and IRF3 (P < 0.05), as well as enhanced cytoplasmic cGAS fluorescence intensity in immunofluorescence analysis. These results demonstrate that elevated extracellular dsDNA can directly damage endothelial cells through cGAS-STING-IRF3 pathway activation, mirroring the endothelial injury observed in SLE patients.<b>Conclusion</b>: Our findings suggest that cell-free dsDNA is a potent inducer of endothelial dysfunction, and that targeting the cGAS-STING-IRF3 axis may offer new therapeutic opportunities for SLE and other diseases marked by elevated extracellular DNA.