Figure 2. Proteomic analysis of the endothelial cell response to the stimulation with extracellular IL-33 mature form IL-33_95–270.

(a) Volcano plot (-log10(p-value) versus log2(fold change)) showing protein expression changes in primary human endothelial cells stimulated for 24 h with 100 ng/ml IL-33_95–270 compared to non-stimulated cells. Statistical analysis was performed from 3 biological replicates by two-sided Student t-test, variance correction and permutation-based FDR control in Perseus. Proteins considered as significantly regulated (FDR<5%, hyperbolic selection curve indicated in grey) are plotted in red. (b) Heat-map of protein intensity following hierarchical clustering of significantly regulated proteins. For each protein the log₂(intensity) measured in the 3 biological replicates (noted A, B, C) is shown for control cells (non-stimulated), and for cells stimulated 6 h or 24 h. Log2 (intensity) values were scaled before clustering by adjusting the lower bound of the 9 data points to zero. Clusters shown on the left illustrate down- regulated proteins (green), moderately up-regulated proteins with maximal induction at 24 h (blue) and strongly up-regulated proteins with early induction (bottom clusters). (c) Schematic illustration of the IL33-induced inflammatory response in primary human endothelial cells. All proteins found to be significantly up-regulated after treatment with IL-33_95–270 for 6 h or 24 h are represented.