Abstract
Purpose :
Age-related macular degeneration (AMD) is the leading cause of visual impairment in the elderly. Oxidative stress and an aged or diseased Bruch’s membrane contribute to the downstream dysfunction seen in retinal pigment epithelial (RPE) cells. The development of robust drug discovery platforms that can identify therapeutics that improve RPE cell function due to these insults would be beneficial. Herein, we demonstrate the use of a phenotypic high-throughput screening (HTS) platform to identify novel small molecules that improve RPE survival in vitro and a blue light damage model of retinal degeneration in vivo.
Methods :
A HTS was conducted to identify compounds that protect RPE cells from oxidative damage. Cell viability was tested in models of RPE stress, including tert-butyl hydroperoxide (TBHP) exposure, ultraviolet-B (UV-B)-mediated light damage and nitrosative stress to the basement membrane. PCR and analysis of mitochondrial function were used to elucidate possible mechanisms of drug treatment. Sprague–Dawley CD-1 rats were exposed to blue light to induce dry AMD. Optical coherence tomography (OCT), hematoxylin and eosin, and immunofluorescence were performed to assess retinal structure. Electroretinography (ERG) was used to assess retinal function.
Results :
Initial HTS of a library with 65,000 synthetic compounds (ChemDiv library) using TBHP, a chemical oxidizing agentidentified two compounds (M414 and M434) that significantly protect RPE from TBHP-induced cell death. M414 and M434 protected human RPE cells from UV-B light damage and enhanced cell viability on nitrite-modified basement membrane. Both compounds improved mitochondrial function and attenuated expression of mitochondrial apoptotic genes after oxidative damage to RPE cells. The retinal mid-layer thickness was significantly decreased after blue-light exposure in rats. The decreased retinal thickness and photoreceptor survival was improved after treatment with M414 and M434. Like the retinal structure changes, functional loss of ERG amplitude (from blue-light exposure) was restored after administration of both compounds.
Conclusions :
Our data demonstrates the capacity of a HTS platform to identify novel small molecules that protect the retina from pathological factors associated with AMD.
This abstract was presented at the 2022 ARVO Annual Meeting, held in Denver, CO, May 1-4, 2022, and virtually.