Figure 4

UFP exposure down-regulates mRNA expressions of endothelial tight junction (TJ) protein and the Notch target gene to disrupt the GVB. mRNA expressions of TJ proteins, including zonula occludens1 (Zo1), claudin 1 (Cldn1), and occludin 1 (Ocln1), and the Notch target genes, including Hairy and enhancer of split-1 (Hes1), were assessed in vitro by cultured human aortic endothelial cells (HAEC). (A) UFP exposure (25 μg·mL⁻¹ for 6 h) inhibited Zo1 and Cldn1 mRNA expressions, whereas Ocln1 mRNA remained unchanged. While Iwr1 treatment (10 μM) diminished overall TJ mRNA expression, LiCl (20 mM) up-regulated Cldn1 and Ocln1 mRNA expression (* p < 0.05 vs. DMSO for Iwr1, H₂O for LiCl, n = 3, ** p < 0.01, *** p < 0.001). (B) UFP exposure (25–50 μg·mL⁻¹ for 6 h) down-regulated both TJ (Zo1 and Cldn1 mRNA) and Notch target genes (Hes1) mRNA expression in a dose-dependent manner (* p < 0.05 vs. H₂O, n = 3). (C) Treatment of Adam10 inhibitor (5 μM) to inhibit Notch receptor activation down-regulated Cldn1, and Hes1 mRNA in a dose-dependent manner (* p < 0.05 vs. DMSO, n = 3, ** p < 0.01, *** p < 0.001) (D) Micro-gavage with Adam10 inhibitor promoted transmigration of FD10 to both AVP and CVP. Micro-injection of NICD mRNA restored UFP- and Adam10 inhibitor-mediated effect. (E) Percentage of embryos exhibiting endoluminal FD10 fluorescence (* p < 0.05 vs. FD10, n = 10 per group).