Mapping the Hypoxic Fitness Landscape of Retinal Pigment Epithelial Cells.

Chronic hypoxia is a hallmark of aging and retinal diseases such as age-related macular degeneration (AMD), yet the molecular mechanisms that enable retinal pigment epithelium (RPE) cells to survive under sustained low-oxygen conditions remain poorly understood. To address this, we conducted transcriptomic profiling and a genome-wide CRISPR-Cas9 loss-of-function screen in ARPE-19 cells exposed to chronic hypoxia (1% and 5% O2), mimicking the retinal disease environment. The CRISPR screen identified genes whose loss compromises RPE viability or fitness under hypoxia, while transcriptomic profiling revealed oxygen-dependent shifts in key functional modules. These findings converged on pathways related to mitochondrial function, extracellular matrix remodeling, vascular signaling, and cell cycle regulation, identifying unique functional nodes specific to RPE cells. These core processes are also implicated in retinal diseases, such as AMD. Together, these complementary approaches provide an integrated view of the molecular networks driving RPE adaptation to hypoxic stress and highlight novel gene candidates that may serve as therapeutic targets in retinal disease.