Fig. 3

Functional relevance of the MWCNT-responsive peptidome. a Venn diagram reflecting functional associations among 73 identified peptides per ontology enrichment analysis. Groups denote the five most-enriched associations per biochemical, pathological, cellular and localization databases, with peptide-precursor protein symbols shown. Serum cumulative inflammatory potential assay results after treating endothelial cells for 4-h in vitro with b the enriched-peptide serum fraction and c after denaturing the peptide fraction. Presented as the mean ± SE, n = 6 serum peptide fractions from replicate mouse exposures per dose, ^#p < 0.05 for effect of denaturing; *p < 0.05 for effect of MWCNT. d Acetylcholine induced vascular relaxation assessed ex vivo using naïve aortic rings treated with the enriched-peptide serum fraction, expressed as a percent recovery towards the pre-contraction tension. Data are presented as the mean ± SE, n = 6 serum peptide fractions from replicate mouse exposures per dose, *p < 0.05. e The hydrodynamic vesicle size distribution for an exosome-enriched size-exclusion serum fraction, plotted as the mean ± SE for bins sized between 30 and 180 nm, n = 3 replicate exosomal serum extracts from n = 6 replicate mouse exposures per dose. Dashed lines denote the curve mean, *p < 0.05. Inset electron micrograph of the serum exosomes; scale bar = 100 nm