Fig. 6: Macrophage-derived CTSC in ECM promotes pulmonary fibrosis via ICAM1 hydrolysis.
From: Extracellular matrix anchored neutrophils drive pulmonary fibrosis in mice
a, b Dot plots from GSE183682 and GSE174725 showing highest CTSC expression in macrophages. c Western blot of CTSC levels in RAW264.7 cells treated with SiO₂. d, e Spatial transcriptomics and IF show elevated CTSC expression in SiO₂-56d mouse lungs. Scale bar = 200 μm. f Clodronate liposome workflow for macrophage depletion to investigate effects on ECM-associated CTSC and rTEM neutrophils. g, h IF showing Ly6G and ICAM1 levels in ECM after macrophage depletion, with Nor-ECM as the control group. Scale bar = 200 μm. i Experimental workflow exploring CTSC’s role in ICAM1 cleavage. PI represents a protease inhibitor that inhibits CTSC function, while Ab refers to an anti-CTSC antibody that blocks CTSC function. j ELISA detecting ICAM1 levels in CM-2, confirming CTSC cleaves neutrophil-derived ICAM1. k, l Fibroblasts co-cultured with CM-2 show elevated COL1A2 and ACTA2 levels. m–o BrdU assay and wound healing assessing fibroblast proliferation (m, n) and migration (o, p) after CM-2 treatment. Representative images are shown from n = 5 independent experiments with similar results. Scale bar = 650 μm. Data are presented as mean ± SEM. n = 5 independent experiments. h: two-way ANOVA, followed by Šídák’s multiple comparisons test. j, compared with Con-CM2: one-way ANOVA, followed by Tukey’s test. l, n, p: Unpaired t test with Welch’s correction. Source data are provided as a Source Data file. Created in BioRender. Chao, J. (2025) https://BioRender.com/ua4330j.
