Fig. 2.

Circulating MWCNT-induced peptides relate to matrix protease activation. a Waterfall plots depicting the MWCNT-induced fold-change among responsive factors within the enriched peptide fraction plotted three-dimensionally against reversed-phase retention time and the charge-reduced protonated mass (MH+). b MMP9 protein abundance in animal-matched lung tissue and BALF 4-h after MWCNT exposure as assessed by ELISA and presented as the mean ± SE, n = 5 replicate mouse exposures per dose, *p < 0.05. c Venn diagram of identified MWCNT-responsive peptides in association with databases of matrix protease substrates and predicted secreted signaling motifs. d Gene expression changes in lung tissue across matrix proteineases of the MMP, ADAM and ADAMTS families, tissue inhibitors of metalloproteinases (TIMPs) and lysosomally-derived cathepsins (CTS) following a 4-h inhalation exposure to MWCNT. Results reported for proteases that exhibited a two-fold or greater response to MWCNT and reached significance at an FDR of 5% as assessed by Illumina BeadChip and presented at the mean response across n = 4 replicate mouse exposures per dose