A genome-scale ORF screen for resilience factors that protect the RPE and restore vision in aged mice

Aging is a complex phenomenon, but therapeutic discovery has largely relied on testing individual hypothesis-driven targets. To search more broadly for protective factors, researchers performed a genome-scale open reading frame (ORF) screen for oxidative-stress resistance in retinal pigment epithelium (RPE) cells, which are vulnerable to oxidative damage during aging.

The screen identified nine protective ORFs, including antioxidant factors and an epithelial-to-mesenchymal transition regulator. It also identified three factors that reduce transcriptomic age, including the cardiac transcription factor NKX2-5. NKX2-5 conferred robust oxidative resilience in vitro and in vivo. Domain dissection revealed that its homeodomain is dispensable for resilience, enabling development of NKX2-5ΔHD, which retained protective activity without detectable toxicity over 14 months.

In middle-aged mice, subretinal NKX2-5ΔHD restored visual and electrophysiological function, and its systemic delivery improved grip strength and reduced frailty in late-aged mice. These findings highlight the value of unbiased, genome-scale gain-of-function screening, as resilience factors normally expressed in other contexts can be reengineered as potential therapeutics for age-related decline in other tissues.