Abstract
Purpose :
Recently, we have developed a novel approach to elucidate the early initiating factors that may underlie the pathology of dry age-related macular degeneration (AMD), and specifically its end-stage Geographic Atrophy (GA). Suppression of claudin-5 levels, the most highly enriched tight junction protein at the inner blood-retinal barrier (iBRB), leads to retinal pigment epithelium (RPE)-like atrophy. Here, we sought to characterise novel animal models that allow us to assess the effect of claudin-5 levels on RPE due to varying claudin-5 expression levels in greater detail to identify the kinetics of damage observed and the downstream effectors that lead to RPE atrophy.
Methods :
We have compared three novel animal models 1) RNAi based inducible claudin-5 knockdown mice, 2) Cldn5+/- mice and 3) C57BL6/J mice sub-retinally injected with adeno-associated virus (AAV) vectors expressing shRNA targeting claudin-5, or non-targeting control to characterise the effect of constant claudin-5 suppression on retinal and RPE integrity. Each cohort of mice were either fed a normal or high cholesterol diet for varying lengths of time to assess RPE atrophy progression. All mice were imaged by optical coherence tomography (OCT) to examine RPE integrity and fundus fluorescein angiography (FFA) to assess retinal blood vessel integrity and compared to littermate controls. Immunohistochemical, protein and transcript analysis was undertaken following sacrifice.
Results :
Assessment of these three mouse models shows that RPE atrophy progression varies depending on the level of claudin-5 expression at the iBRB and is exacerbated when addition of high cholesterol chow was provided as determined by OCT and FFA.
Conclusions :
These novel animal models may be beneficial in understanding GA pathology and development in greater detail. Targeted stabilization and regulation of claudin-5 expression at the inner retinal vasculature may have therapeutic potential for preventing GA onset and development.
This is a 2021 ARVO Annual Meeting abstract.