Fig. 4.

RPE dystrophy is associated with barrier function loss in VEGF188/188 mice. (A) Flat-mount preparation of 14-month-old wt mice and VEGF188/188 showed abnormal distribution of the junctional proteins in RPE layer of transgenic mice. In wt, RPE formed a regular honeycomb pattern. In VEGF188/188, the RPE organization is disturbed and atrophic revealing the choroidal vessel underneath (CC). In the RPE lesions, the gap-junction protein β-catenin has lost its characteristic membranous association (arrows). (B) Abnormal β-catenin distribution was accompanied by a reduction of protein expression showed by Western blot on 16-month-old choroid-RPE samples (n = 6). (C) Aberrant ZO1 localization was also observed in the VEGF188/188 mice. (D) No changes in ZO1 protein level were detected. Immunoprecipitation for occludin followed by ZO1 Western blotting revealed a 45% reduction in association between ZO1 and occludin (n = 3). (E) Over time, the limited RPE lesions observed at 14 months (see panels A and C) expanded significantly leading to a major loss in the integrity of the RPE layer of 18-month-old VEGF188/188 mice. [Scale bar, 50 μm (A and C); scale bar, 100 μm (E).]