Project Summary/Abstract Optic neuropathies and retinal diseases are leading causes of irreversible blindness worldwide. Currently, there are no therapies to restore vision loss. Whole eye transplants could restore vision if the neural circuits between the eye and the brain could be restored. The long-term goal of this proposal is to develop therapies that regenerate lost retinofugal pathways and enable whole eye transplants. In experimental spinal cord injury models, neural stem cells (NSCs) have been used to form neuronal relays that restore injured connections and function. Similarly, NSCs have demonstrated the capacity to form neuronal relays in the optic nerve and integrate into the injured visual system. The overall objectives in this application are to (i) determine the degree of visual function recovery from long-term NSC-derived neuronal relays in the injured optic nerve and (ii) develop methods to guide neuronal relay axons through the optic chiasm and to appropriate synaptic targets. The central hypothesis is that stem cell-derived neurons transplanted into the optic nerve form neuronal relays that can be guided to appropriate targets to restore vision-related function. This proposal will test this hypothesis by pursuing the following specific aims: 1) measure the functional recovery from long-term optic nerve grafted NSCs in the injured visual system, 2) investigate the role of canonical chiasmal guidance cues on neuronal relay axon guidance, and 3) target neuronal relay axons to host vision-associated nuclei. In the first aim, rodent optic nerve transection models will be treated with NSCs to restore retinofugal connections with neuronal relays. Long-term integration and function of NSC-derived neuronal relays in restoring vision will be evaluated with visual function testing and histological assessments for the structural indicators necessary for effective neuronal relay conduction. For the second aim, NSCs with genetic modifications of canonical optic chiasm guidance pathways that are important in development will be transplanted into a rodent optic nerve transection model. These modified NSCs will be used to assess the effect of developmental guidance cues that persist in the adult optic chiasm on the decussation of growing axons in the injured visual system and the manipulability of those pathways. In the final aim, transduction of vision-associated nuclei to express neurotrophins using an adeno-associated virus will be used to guide NSC-derived optic nerve neuronal relay axons to innervate specific targets and facilitate recovery of visual function. The research proposed is innovative because it overcomes current limitations in optic nerve regeneration by leveraging stem cells and enables research on important downstream considerations necessary for successful optic nerve regeneration. The proposed studies are significant because they develop a novel use of stem cells to form neuronal relays to regenerate the optic nerve and adv...