Fig. 5

EV-delivered miR-186 decreases the expression of DKK1 through targeting SOX4 to impair fibroblast activation. a The significant co-expression relationship between SOX4 and DKK1 predicted by MEM (https://biit.cs.ut.ee/mem/index.cgi) (p = 3.1e−05). b The relationship between SOX4 and DKK1 predicted by hTFtarget (http://bioinfo.life.hust.edu.cn/hTFtarget#!/). c The PPI network of DKK1 and its related genes predicted by String (https://string-db.org) (the circle: the core degree of the gene = 10). d KEGG pathway map of DKK1 and the related genes analyzed by KOBAS (http://kobas.cbi.pku.edu.cn) (horizontal axis: enriched pathway; lateral axis: the number of genes enriched in this pathway; red indicates high significance; blue indicates low significance). e, f DKK1 mRNA (e) and protein (f) expression in lung tissues of patients with IPF (n = 48) and control donors (n = 16) measured by RT-qPCR and western blot analysis. g The correlation of DKK1 expression with SOX4 expression in clinical samples. h The silencing efficiency of sh-SOX4-1 and sh-SOX4-2 determined by RT-qPCR. i, j DKK1 mRNA (i) and protein (j) expression in fibroblasts after SOX4 silencing measured by RT-qPCR and Western blot analysis. k SOX4 and DKK1 mRNA expression in the fibroblasts after SOX4 knockdown/DKK1 overexpression determined by RT-qPCR. l The proliferation of LL29 fibroblasts after SOX4 knockdown/DKK1 overexpression analyzed by CCK8. m The migration and invasion of fibroblasts after SOX4 knockdown/DKK1 overexpression evaluated by Transwell assay. n, o Cell cycle (n) and apoptosis (o) after SOX4 knockdown/DKK1 overexpression determined by flow cytometry. p, q The mRNA (p) and protein (q) expression of α-SMA and collagen I in the fibroblasts after SOX4 knockdown/DKK1 overexpression measured by RT-qPCR and western blot analysis. r miR-186 expression in fibroblasts treated with EV-miR-186 after SOX4 knockdown determined by RT-qPCR. s The protein expression of SOX4 and DKK1 in fibroblasts treated with EV-miR-186 after SOX4 knockdown measured by Western blot analysis. In k–p, *p < 0.05 vs. the fibroblasts co-transfected with scramble and oe-NC; ^#p < 0.05 vs. the fibroblasts co-transfected with sh-SOX4 and oe-NC. In r and s, *p < 0.05 vs. the fibroblasts treated with sh-SOX4, and PBS. Differences between two groups were compared by unpaired t test, while differences among groups were determined by one-way ANOVA. Besides, the comparison of the data in each group at different time points was analyzed by two-way ANOVA. Pearson correlation was used to analyze the correlation between SOX4 and DKK1. The experiment was repeated three times