Fig. 4: Polystyrene nanoplastic-induced endothelial leakiness is independent of ROS formation and endocytosis but is related to VE-cadherin signaling pathway and actin remodeling.

a Blocking endocytosis with inhibitors or ROS inhibition did not prevent leakiness of PS nanoplastic. However, Src kinase inhibitor PP1 and ROCK inhibitor Y-27632 affected the leakiness of PS nanoplastic. HUVECs were treated with Src kinase inhibitor PP1 (10 µM), rho-associated protein kinase (ROCK) inhibitor Y-27632 (10 µM), endocytosis inhibitors (5 mM methyl-β-cyclodextrin (MβCD) and 10 µM monodansylcadaverine (MDC)), or ROS inhibitor (5 mM N-Acetyl-L-cysteine (NAC)) for 1 h prior to b 0.05 mg/mL or c 0.5 mg/mL PS nanoplastic treatment. PP1 and Y-27632 significantly reduced the fold of FITC-dextran penetration compared to their respective counterparts without inhibitor treatments. MβCD, MDC, or NAC did not significantly decrease the fold of FITC-dextran penetration compared to their respective counterparts without inhibitor treatments. Data are expressed as means ± SD. Biologically independent samples were used (n = 3). Statistical analysis was performed through one-way ANOVA followed by Tukey’s multiple comparison tests. The derived P values were inserted in the panel. Western blot analysis of VE-cadherin and its phosphorylation levels: d 0.05 mg/mL or e 0.5 mg/mL PS nanoplastic treatment induced tyrosine phosphorylation of VE-cadherin at Y658 and Y731. However, PP1 effectively inhibited PS nanoplastic-induced phosphorylation of VE-cadherin at Y658 and Y731. f Semi-quantitative analysis revealed activation of VE-cadherin (VEC) signaling exposed to PS nanoplastic (0.05 or 0.5 mg/mL). Data are expressed as means ± SD (n = 3 biologically independent experiments). Statistical analysis was performed through two-way ANOVA followed by Tukey’s multiple comparison tests. The derived P values were inserted in the panel. Source data are provided as a Source Data file.