Although mature retinal ganglion cells (RGCs) are normally unable to regenerate axons following optic nerve damage, studies from several labs, including those participating in this collaboration, have identified cellular, molecular, and physiological manipulations that enable some RGCs to regenerate injured axons from the eye to the brain. In spite of these efforts, however, the number of RGCs that survive after optic nerve injury and successfully regenerate axons into the brain remains small, thereby limiting meaningful visual recovery. The proposed research will combine a strong pro-regenerative therapy with novel transcriptomic and proteomic approaches and cutting-edge bioinformatic methods to identify new transcripts and proteins associated with the initiation and execution of a successful regenerative program. We will investigate the temporal sequence of changes in gene expression, protein translation, and protein transport down the regenerating optic nerve as mature RGCs undergo a transition from a normal intact state into a robust growth state, identify transcripts and proteins selectively expressed in the subset of RGCs that successfully extends axons into the nerve, and characterize the RGC subtypes with the highest potential to regenerate axons. 100-150 of the top candidate genes identified in the discovery phase will be tested for their ability to promote axon outgrowth in immunopurified RGCs in culture, and lead candidates from the intermediate screen will be tested for their ability to substantially augment levels of optic nerve regeneration in vivo, either in isolation or in combination with established pro-regenerative therapies. These latter studies will investigate the targeting of axons to appropriate central visual nuclei and tests of visual recovery. The integrated approach proposed here directly addresses the goal of identifying novel molecular targets to re- establish visual circuitry after injury to the visual system.
The inability of mature retinal ganglion cells to regenerate injured axons has devastating consequences for victims of traumatic, ischemic, or degenerative damage to the optic nerve. This project will combine cutting-edge transcriptomics, proteomics, bioinformatics, cell-based and in vivo validation methods to identify key molecules that enable RGCs to regenerate injured axons and reestablish the appropriate pattern of connections between the eye and brain.
| Seabrook, Tania A; Burbridge, Timothy J; Crair, Michael C et al. (2017) Architecture, Function, and Assembly of the Mouse Visual System. Annu Rev Neurosci 40:499-538 |
