Transplanting light-dependent reactions for mammalian eye photosynthesis

Mammalian eyes are exposed to visible light but cannot perform photosynthesis. Here, we show that introducing a nanoscale, structurally and functionally preserved thylakoid system, LEAF (light-reaction enriched thylakoid NADPH-foundry), into corneal cells enables light-driven bona fide photosynthetic production of NADPH and ATP, similar to plant leaves, which alleviates oxidative stress and inflammation. LEAF acts in two domains. Intracellularly, it integrates with host cells to supply NADPH and ATP via intact photosynthetic electron transport, restoring redox balance. Extracellularly, photosynthesized NADPH enhances endogeneous antioxidant enzyme activity and reduces reactive oxygen species in the local environment. These results establish a strategy for using light as an energy input in mammalian metabolic systems and suggest a possible cross-kingdom, endosymbiosis-like interaction in which animal cells derive functional benefits from plant-derived photosynthetic neo-organelles.