Fig. 6

Monocyte transmigration and endothelial inflammatory response to key cytokines in the fibrotic secretome. (a) Monocytes circulated in EC-seeded fluidic hToC devices were observed in phase contrast time-lapse recordings over 2 h. Representative images of the final frame of the 2-h videos are shown. (b) Percent transmigration quantification of N = 3 experimental replicates per condition. Results demonstrated significantly elevated monocyte transmigration levels in response to TNF-α stimulated ECs compared to the negative control (p < 0.001) and TGF-β1 stimulation condition (p = 0.005). Similarly, MCP-1 and TGF-β1 + MCP-1 induced significantly increased percent transmigration compared to the negative control (p < 0.001) and TGF-β1 stimulation condition (p = 0.020). One-way ANOVA with Tukey’s post-hoc test was used, *p < 0.05, **p < 0.01, ***p < 0.001. (c) Following the 2-h transmigration experiment, devices were stained for ICAM-1 (red), PSGL-1 (green), and Hoechst (blue). Representative images of devices with and without monocytes in each stimulation condition are shown. We observed a substantial increase in ICAM-1 upon TNF-α stimulation regardless of the presence of circulating monocytes. The MCP-1, TGF-β1, and TGF-β1 + MCP-1 conditions, on the other hand, did not induce ICAM-1 upregulation. However, upon monocyte circulation, we observed an increase in ICAM-1 expression in these three conditions.