Limbal niche cell-derived exosomes accelerate corneal epithelial repair through PI3K/Akt activation and FOXO3 inhibition

Corneal epithelial defects (CEDs) remain a major challenge in ophthalmology, with limited options for severe or recurrent cases. Here, we isolated and characterized exosomes derived from human limbal niche cells (LNC-exo) and evaluated their therapeutic potential for corneal epithelial wound healing. LNC-exo were purified via differential ultracentrifugation and characterized by transmission electron microscopy (TEM), nanoparticle tracking analysis (NTA), and Western blot. Small RNA sequencing revealed that LNC-exo are enriched in miRNAs targeting the PI3K/Akt and FOXO signaling pathways. In vitro, LNC-exo dose-dependently promoted the proliferation and migration of immortalized human corneal epithelial cells (HCE-T), characterized by the activation of PI3K/Akt and suppression of FOXO3, as well as the upregulation of Laminin, Integrin, and Cyclin D1; these pro-regenerative effects were significantly attenuated by the PI3K inhibitor LY294002. Furthermore, in a mouse corneal epithelial defect model, topical administration of LNC-exo markedly accelerated wound closure with efficacy comparable to that of recombinant human basic fibroblast growth factor (rh-bFGF). Our findings demonstrate that LNC-exo enhance corneal epithelial regeneration by modulating the PI3K/Akt/FOXO3 signaling axis and suggest that LNC-exo represent a promising cell-free therapeutic agent for the treatment of corneal epithelial disorders.