Western blotting was performed as previously described [12 (link),13 (link)]. Briefly, cell lysates or whole retina lysates were separated onto precast tris-glycine gels (Invitrogen, Carlsbad, CA) and then blotted onto nitrocellulose membrane. After blocking in TBST, membranes were treated with Epac1, TNFAIP3, TRAF6, TNFα, phosphorylated and total NF-kB, phosphorylated and total IkB, occludin, ZO-1 (Abcam, Cambridge, MA), or beta actin (Santa Cruz Biotechnology, Santa Cruz, CA) primary antibodies. Secondary species-appropriate antibodies labeled with horseradish peroxidase were applied after the primary antibodies. Chemiluminescence (Thermo Scientific, Pittsburgh, PA) was used to visualize antigen–antibody complexes. Images were acquired on an Azure C500 (Azure Biosystems, Dublin, CA), and optical densities were measured using Image Studio Lite software (Lincoln, NE).