Fig. 1.

Self-dsDNA release is central to silica-induced lung inflammation and type I IFN response. a–m Silica microparticles (1 mg/mouse, i.t.) or saline were administered in WT mice and parameters were analyzed on day 7. a Concentration of extracellular dsDNA in the acellular fractions of bronchoalveolar lavage fluid (BALF). b–d Tmem173, Mb21d1, Ifnα, and Ifnβ transcripts in the lungs and normalized to Gapdh expression. e Lung CXCL10 determined by ELISA and IFN-αβ proteins quantified by multiplex immunoassay. f Correlation between extracellular dsDNA concentrations and type I IFN gene expression. g Annexin V/PI flow cytometry analysis pre-gated on singlet cells. h Correlation between dead cells and extracellular dsDNA. i Increased nuclear DNA (nDNA) and mitochondrial DNA (mtDNA) in the BALF after silica exposure. j Immunoblots of caspase 3 (Casp3), cleaved caspase 3 (c-Casp3), gasdermin D (GSDMD), MLKL, and phosphorylated-MLKL (p-MLKL), normalized to β-actin. Immunoblot quantifications of (k) c-Casp3, (l) c-GSDMD, and (m) p-MLKL. n–u Silica microparticles administered with DNase I (200 µg/mouse, i.p.) as indicated (n). o Extracellular dsDNA in BALF acellular fraction. p Lung immunoblots of phospho-STING, STING, phospho-TBK1, TBK1, phospho-IRF3, IRF3, caspase 3 (Casp3), cleaved caspase 3 (c-Casp3), MLKL, and phosphorylated-MLKL (p-MLKL), with β-actin as a reference. q Quantification of STING dimer, relative to β-actin. r STING immunoblots under 5% reducing (left) or 1% 2-mercaptoethanol seminative conditions (2-ME; right). s Lung confocal images of DNA dye Draq5 (cyan) and STING (red). Bars, 20 µm. t Pulmonary IFN-αβ and CXCL10. u Neutrophils, macrophages, and protein extravasation in the BALF. *p < 0.05, **p < 0.01, ***p < 0.001, ****p < 0.0001 (Kruskal–Wallis test followed by Dunn post test). The correlation analysis was nonparametric (Spearman correlation). Data are mean ± SEM representative of two independent experiments (a–f: mice per group: n = 5 or 10 (WT NaCl), n = 8 or 10 (WT silica); g–h: mice per group: n = 5 (WT NaCl), n = 5 (WT silica); i–n: mice per group, n = 5 or 10 (WT NaCl), n = 5 or 10 (WT silica), and n = 5 (WT silica + DNase I)). Immunoblots representative of n = 6 samples from three independent experiments (j, p), or n = 8 samples from two independent experiments (r), quantified in bargraphs with n = 4. Each symbol represents an individual mouse. Source data are provided as a Source Data file