Fig. 2.

Circulating DNA and CXCL10 in the airways of silicosis patients, STING, and type I IFN pathway activation in ILD patient lungs. a, b Presence of (a) dsDNA in the plasma and (b) CXCL10 in the sputum of patients with silicosis (ILO 5–12, see Table 1), as compared with healthy individuals (ILO 0). c–f Human lung tissue samples of ILD patients treated or not with cortisone (see Table 2). c Confocal images of DNA dye Draq5 (cyan) and STING (red). Bars, 50 µm. Bars, 20 µm for zoomed regions. d Immunoblots of phosphorylated-STING (p-STING), STING, TBK1, phospho-TBK1, IRF3, phospho-IRF3, and β-actin. STING dimers quantification. e CXCL10 levels. f Correlation between STING dimers and epithelial damage scored on human histological tissue sections for necrotic cells, desquamation or denudation, and flattening of the epithelial barrier (indicated by arrows). Control lung tissue (patient G) and fibrotic area (patient D). Bars, 100 µm. g–n Human PBMCs were stimulated with silica microparticles (250 µg/mL) for 18 h, transfected with c-di-AMP (6 µg/mL) or unstimulated. g Extracellular dsDNA in cell supernatant, h IFNβ transcript, i correlation between IFNβ transcripts and released dsDNA. (j) CXCL10. (k) Confocal images of DNA dye Draq5 (cyan) and STING (red). Bars, 5 µm. l Immunoblots of phospho-STING, STING, phospho-TBK1, TBK1, phospho-IRF3, IRF3, and β-actin. m Flow cytometry annexin V/PI analysis gated on singlet cells. n Correlations between dead cells and extracellular dsDNA or IFNβ transcripts. *p < 0.05, **p < 0.01, ***p < 0.001, ****p < 0.0001 (Student's t test). The correlation analysis was nonparametric (Spearman correlation). Data are mean ± SEM representative of two independent experiments. a, b Plasma samples from n = 10 healthy controls and n = 21 silicosis patients; b sputum samples from n = 9 healthy controls and n = 13 silicosis patients. c–f c: Confocal image representative of three patients; d: immunoblots shown from left to right for ILD patients H, G, C, A (see Table 2), representative of n = 3 cortisone-treated ILD patients and n = 18 untreated-ILD patients, from three independent experiments, shown in d–f. g–k PBMC from n = 6 donors per group. l Immunoblots representative of n = 6 donors from two independent experiments. m–n Four donors per group, and are representative of at least two independent experiments with similar results (g–n). Each symbol represents an individual. Source data are provided as a Source Data file