Cell type focused, high-throughput compound screen in human retinal organoids reveals targets to counteract cone photoreceptor degeneration

Abstract

Purpose : Cone photoreceptors are essential for high resolution human vision and enable us to read and recognize faces. In several retinal diseases cones die which lead to blindness. To find molecular targets which could be modified to slow down the death of cones, we performed a cone-focused high-throughput compound screen in human retinal organoids.

Methods : We grew ~20’000 organoids, each of which were multilayered and contained many of the same cell types as the human retina. We fluorescently labeled close to 100% of cones in each organoid using cell-type targeted viral vectors and imaged them in 3D, cell-by-cell and organoid-by-organoid, using live high-throughput confocal microscopy. We induced the death of cones by withdrawing glucose in the presence or absence of one of 2’732 chemical compounds of a “mode of action” library, in which the target of each compound is known and well characterized. We quantified cone loss using a cell-detection algorithm that we developed, based on 3D cone images before and after glucose withdrawal.

Results : In the absence of compounds, ~40% of cones died within 7 days. Several compounds induced more degeneration compared to controls, and broad spectrum HDAC inhibitors were among those that consistently induced cone-degeneration. Importantly, few compounds highly significantly counteracted cone degeneration and among them were some that acted at sub micromolar ranges.

Conclusions : Remarkably all the highly potent compounds had the same gene target which points to a pathway that can be further explored to counteract cone photoreceptor degeneration in human patients.

This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.