Figure 4.

γ-Secretase and PS1 suppress CNV. (A) Representative confocal images of laser-induced CNV lesions in eyes. Eyes had either received intravitreal injection of PEDF, DAPT, or PEDF + DAPT at the time of laser injury, or AAV2 infection 3 weeks before receiving laser burns. Saline alone acted as the control. Animals were euthanized 14 days post laser injury and RPE choroidal flat mounts were stained with a vascular specific marker, agglutinin-TRITC conjugate (red) to visualize the CNV lesions by confocal microscopy. Note the reduction in lesion size in mouse eyes treated with PEDF or AAV2-PS1 and that the protective effect of PEDF was blocked by the addition of γ-secretase inhibitor. (B) Quantitative assessment using confocal microscopy to measure the volume of the vascular lesions described in (A) (mean ± SEM, n = 12). (C) For PS1 and nicastrin knockdown studies 1 μL of siRNAs against mouse PS1 nicastrin or negative control siRNA at a concentration of 2 μg/μL was given by intravitreal injection at the time of laser injury. Quantitative assessment was undertaken using confocal microscopy to measure the volume of the CNV lesions (mean ± SEM, n = 12). (D) Representative micrographs of transverse sections through the retina and choroid stained with the vascular fluorescent dye, agglutinin-FITC conjugate (green) and counter nuclear stained with DAPI which demonstrate a significant suppression of choroidal vascular outgrowth into the photoreceptor layer by overexpression of PS1. Representative H&E sections are shown on the left to provide orientation.