Connectomes are Rosetta Stones for discovering how retinas are wired, and revealing how that wiring becomes corrupted in disease. This proposal is crafted around assembly, annotation and analysis of ultrastructural connectomes from normal human retina, providing a normal circuit topology framework to compare against companion human retinal patho-connectomes from human retinitis pigmentosa (RP) and age- related macular degeneration (AMD), hypothesizing that 1) new networks including rod-cone crossover, bipolar cell coupling, nested inhibition, and neurogliovascular (NGV) architectures, structures (cistern synapses, plaques, adherens) are common across mammalians, and 2) seeks to explore how these network topologies are altered in retinal disease. Prior work unmasked unexpected, pervasive complexities in mammalian retina, informing modeling of retinal prosthetics. Speci?c Aim 1. Construction / annotation of a ~100 TB connectome for human (H-RC3). Signi?cance. H-RC3 allows analyses of human cone channels, describing how these networks are blended with existing channels. We hypothesize 1) novel crossover / coupling motifs are present in both midget and diffuse bipolar cells and 2) nested feedback/feedforward architectures are key to midget pathways. With TEM-compliant molecular markers, we will map the heterocellular architecture of the human NGV system in comparison with RC1 and M- RC2. Speci?c Aim 2. Construction / initial annotation of 2 ~50TB connectomes of human RP retina (HRPC1,2- RC4,5). Signi?cance. Annotation/analysis of RC1 revealed unexpected retinal architectures in?uencing all networks: refactored IPL lamination, extensive rod-cone bipolar-amacrine crossover networks, complex homocellular / heterocellular / in-class / cross class coupling, selective bipolar cell loading by ganglion cells. Presuming these networks are present in humans, direct comparisons from SA 1 should establish how networks are altered in human RP, serving as guides to understanding RP progression, and reveal targets for therapeutic intervention. Speci?c Aim 3. Construction / initial annotation of 1 ~80TB connectome of human AMD retina (HRPC3-RC6). Signi?cance. HRPC3-RC6 will allow exploration of altered neuronal, glial and vascular networks in AMD, exploring whether retinal remodeling and plasticity are similar for different retinal disease mechanisms. We now know retinal remodeling occurs in AMD, and that GABAergic amacrine cell networks are involved. We do not know if the rules behind retinal network alterations are similar across disease pro?les such as RP. Early evidence suggests photoreceptor degeneration, remodeling and progressive neural atrophy are separate processes. Testing this in non-RP models will guide understanding and create a complete connectome database of AMD retina that includes the choroid, neural and glial components.
This proposal is based on the new technologies of connectomics and graph mathematics to build complete maps of retinal nerve cells, retinal blood vessels, and their communication rules in normal human and diseased human retinas. These maps will provide a fundamental framework for understanding normal vision and events underlying retinal disease, especially how we might repair retinal degenerations such as retinitis pigmentosa and age-related macular degeneration.
