Fig. 6

Increased levels of serum CCL17 reflecting an increase in CCL17 in lung tissues during progressive fibrosis. (A) A representative image of immunohistochemistry for CCL17 using lung sections from controls and PPF cases. Magnification, 400×. Arrows indicate alveolar macrophages. (B) Western blotting for evaluating CCL17 in 10 lung tissue specimens, including 5 PPF surgical specimens and 5 control tissues. A representative blot is shown at the upper panel. (C) Schematic representation of the experimental protocol used for the measurement of CCL17 levels of lung tissues and serum from bleomycin-induced pulmonary fibrosis model mice. (D) Representative Azan staining of lung tissues. Magnification, 200×. (E, F) Western blotting analysis of CCL17 in lung tissues and quantification of the levels of CCL17. (G) The serum levels of CCL17 measured by an enzyme-linked immunosorbent assay kit. (E–G) n = 3–5 mice per group. (H) Spearman correlation between CCL17 levels in lung tissues and those in serum. (I) Uniform Manifold Approximation and Projection embedding of single-cell transcriptomes from 77,656 cells from 5 control mice (on day 0) and 20 bleomycin-induced mouse lungs (on days 3, 7, 14, 28, n = 5 mice per group) annotated by cell type. (J) Density plots of Ccl17 mRNA expression levels. (K) Changes in the expression of Ccl17 mRNA by pseudobulk analysis. n = 5 mice per group. The bars indicate the mean in each of the five mice. (F, G, K) The levels were compared by analysis of variance (ANOVA), and Dunnett’s method was applied to adjust for the ANOVA P values. *P < 0.05; **P < 0.01. CCL, C-C motif chemokine ligand; cDC, conventional dendritic cells; MoMac, monocytes and macrophages; PPF, progressive pulmonary fibrosis