Stress Granules and Retinal Degeneration

The formation of stress granules (SGs) – cytoplasmic biocondensates that form in response to cellular stress – in the retina can be induced by prolonged exposure to LED light, a known environmental stressor that can contribute to retinal degeneration (RD), a new IOVS study has determined.

Conducted on rat retinas, the study focused on SGs to determine the role they might play in retinal degeneration (RD). Using immunohistochemistry and RNA fluorescence in situ hybridization techniques, the researchers detected SG markers, such as G3BP1 and eIF3, confirming the presence of these granules in different retinal layers.

Their results reveal that retinal ganglion cells (RGCs) and inner nuclear layer (INL) cells exhibit the highest SG formation, while outer nuclear layer (ONL) cells show minimal SG presence. A significant finding of the study was the increased SG formation in retinas exposed to continuous LED light for two-eight days compared to those maintained under normal light/dark cycles. This finding suggests that SGs may play a role in protecting retinal cells from excessive light-induced stress. Additionally, experiments involving sodium arsenite treatment, a known SG inducer, validated that stress granules can be artificially induced in retinal cells, supporting the hypothesis that these granules are part of a cellular stress response mechanism.

The authors concluded that SGs may serve as an adaptive defense against light-induced oxidative stress, potentially contributing to cell survival in conditions of excessive light exposure. Their findings – the first to characterize SGs in mammalian retina – provide a foundation for further research into how SGs could be leveraged in the development of therapeutic interventions for retinal degenerative diseases.