PROJECT TITLE Photoreceptor Regeneration in a Murine Model of Leber Congenital Amaurosis ABSTRACT Leber congenital amaurosis (LCA) is an early-onset, severe inherited retinal degeneration that results in childhood blindness. Gene therapy can effectively restore visual function in the Lca5gt/gt mouse model of the disease when delivered to neonatal mice before significant retinal degeneration is present. However, in moderate- and late- stage disease after photoreceptor cell death has occurred, gene therapy is no longer effective. Cell-based therapies hold great promise for regenerating photoreceptors in late-stage retinal degenerations, but progress has been limited by low efficiencies of integration and complex cellular interactions with existing retinal cells. Photoreceptor precursors represent a heterogeneous pool of diverse cells types that have the potential to differentiate into mature photoreceptor cells in the developing and diseased retina. Using unbiased single-cell RNA transcriptomics, I identified several novel populations of Crx+ photoreceptor precursors including Crx+/Nfix+ and Crx+/Slc39a1+ cells. The scientific objectives of this proposal are to regenerate photoreceptors in the Lca5gt/gt mouse model of retinal degeneration, by the transplantation of these novel populations of photoreceptor precursors and by the activation of endogenous repair pathways in Mller glia.
The Aims of the proposal are 1) Subretinal transplantation of Crx+/Nfix+ and Crx+/Slc39a1+ progenitor cells in Lca5gt/gt mice, and 2) Activation of endogenous Mller glial repair pathways by gene therapy in Lca5gt/gt mice. In addition to these scientific contributions, this proposal outlines a structured, focused training plan that will equip me with the skills and expertise that will serve as the foundation for my career in developing cell-based therapies for retinal disease. The Department of Ophthalmology at the University of Pennsylvania is an ideal environment for training physician scientists in ophthalmic research, and will provide the protected time, resources, and mentorship needed for a successful transition to independence.
Retinal diseases are one of the leading causes of blindness worldwide and there is currently no treatment to restore vision after photoreceptor cell death. I have discovered novel populations of photoreceptor precursor cells that contribute to normal retinal development and may restore visual function when transplanted or endogenously activated in mouse models of retinal degeneration. Understanding the potential of these cells to regenerate photoreceptors in late-stage retinal degenerations may lead to new potential therapies for blinding diseases.
