• Development and Characterization of Transgenic Models for Studying Progressive Retinal Degeneration and Regeneration

      Zuber, Michael; Yueh Ku, Ray (2017)
      Vision is the sense that human beings rely on the most in the daily life. The irreversibility of retinal damage has been a great challenge to the modern medicine and remains an interest of research in hope of treating, even curing the loss of vision. The work presented in this dissertationutilizes transgenic Xenopus. laevisas an animal model to investigate the possibility of studying progressive retinal degeneration in a species that is known for robust regeneration of damaged retina. I investigated the expression of intermediate filament proteins during retinal gliosis, which has been suggested to be an inhibitory component that prevents effective treatment in degenerating retina. In order to understand the response of retinal bipolar cells in degenerating X. laevisretina, I characterized the expression pattern of metabotropoic glutamate receptor 6 (grm6) and the transgenic X. laevismodel that expresses eGFP under the control of mouse Grm6 promoter in the retina.As a follow up study of a previous study published by our lab,I optimized the condition of using F2 transgenic animals in preparation of a long term study of retinal degeneration in X. laevis. In conclusion, the work in my thesis includes development of tools to further the understanding of retinal degeneration and regeneration in transgenic X. laevis.
    • The Role of Laminins in the Retinal Vascular Basement Membrane

      Brunken, William J.; Watters, Jared (2021-11)
      The vascular basement membrane (vBM) of the central nervous system (CNS) is a highly specialized structure that is composed of various extracellular matrix (ECM) proteins and has many functions, including providing a point of adhesion for the cells of the vasculature, serving as a physical barrier, and providing an interface for communication with endothelial cells. One family of ECM molecules, laminins, are responsible for many of these specialized functions. There are 16 known isoforms of laminin, each consisting of a single α, β, and γ-chain. The distribution of these isoforms in the CNS vBM, however, remains unknown. Here, we used the retina to examine the distribution of laminin chains in the CNS vBM throughout development, as well as the roles of β2-containing laminins in vBM organization and γ3-containing laminins in arterial morphogenesis. The results presented in Chapter 2 demonstrate that there are dramatic changes in the temporal and spatial patterning of many of the laminin chains in the retinal vasculature throughout development, particularly the α2, α5, and γ3-chains. We deleted a key component of the CNS vBM, the laminin β2-chain, to gain a deeper understanding of how laminins affect vBM structure. Deletion of the β2-chain leads to decreased expression of several partner chains, including α2, α5, and γ3. Interestingly, the deletion of laminin β2 also leads to increased deposition of two other ECM molecules, agrin and perlecan, in the BMs of retinal veins and arteries, respectively. We also provide strong evidence that astrocytes contribute laminin 221 to the retinal vBM and that this laminin may directly regulate AQP4 expression in vascular associated astrocytic endfeet. The results presented in Chapter 3 demonstrate that laminins are involved in regulating arterial morphogenesis. Specifically, we found that γ3-containing laminins signal through dystroglycan to induce Dll4-Notch signaling, leading to decreased vascular branching and increased smooth muscle coverage: hallmarks of the arterial phenotype. Taken together, the work presented here further elucidates the structural and functional roles for laminins in the CNS vBM.