(A) Administration of 1 ng/mL VEGF to ARPE 19 cells decreased TEER significantly; reduction in TEER was blocked by TSA (100 nM) pretreatment. (B) VEGF treated ARPE19 cells were lysed after 6 h and blotted for Ac-α-tubulin; β-actin was used as an internal control. 1 h pre-treatment with 100 nM TSA (a pan-HDAC inhibitor) prevented the effect of Glyc-alb, increasing Ac-α-tubulin well above basal levels seen with Alb alone. ARPE19 cells showed an increase in HDAC1/2/3/6 activity (C) and HDAC6 activity (D) at 6 h post treatment with VEGF (1 ng/mL) compared to the administration of the same concentration of Alb; this increase was blocked with TSA pretreatment. Values represent means ± SE of individual measurements normalized to average TEER at 0 h, analyzed by Student T-test. **p<0.01, ***p<0.001. Column numbers represent n for each condition. Legend: Ac-α-tubulin, acetyl-α-tubulin; Alb, albumin; HDAC, histone deacetylase; TEER, transepithelial electrical resistance; TSA, trichostatin-A; VEGF, vascular endothelial growth factor.