Pluripotent Stem Cell Derived 3D Retinas for Studies of Early Onset Retinal Degeneration

项目总结/文摘:

Project Summary/Abstract: Retinal degenerative (RD) diseases, such as Retinitis pigmentosa (RP) and Leber congenital amaurosis (LCA), cause dysfunction and cell death of photoreceptor (PR) cells, ultimately leading to blindness. While not classically considered a retinal degeneration, Alzheimer’s disease (AD) also exhibits many hallmarks of hereditary retinal degenerations. In both AD and hereditary photoreceptor degenerations, like LCA, activated microglia are intimately associated with dystrophic regions where they participate in neuroinflammatory processes. The original AIMs of the funded parent grant sought to study the role of AIPL1 mutations in the onset of early onset retinal degeneration. While this will no doubt uncover many fascinating findings about the pathogenesis of this debilitating disease, this model is lacking a key element that is found in vivo, namely the presence of microglia. In addition to providing support for retinal lamination during development, microglia also participate in neuroinflammatory processes. In the current proposal we will build upon our existing LCA model by incorporating microglia into developing 3D retinal organoids which will be more physiologic and capable of responding to dying cells during RD as occurs in vivo. Furthermore, we will include Alzheimer’s patient derived iPSCs to build 3D retinas to model AD based dystrophy. This is extremely important because if microglia serve a similar role in different forms of RD this would give us a common molecular target. Our proposed microglia work is highly synergistic with the AIMs of the original grant since integrating microglia into our existing 3D retina model will enhance not only our ongoing LCA studies but also will enable us to branch out into a new model of RD based on Alzheimer’s disease. A central hypothesis is that human PSC derived 3D retina organoids with LCA and AD associated mutations will recapitulate human retinal dystrophy resulting in PR loss, increased microglial activation and accumulation of markers characteristic of AD. While studying microglia in LCA tissue by itself is a noteworthy endeavor, exploring AD tissue in a similar fashion will add important information on general responses of microglia to cell stress and cell death. This proposal will bridge two innovative technologies; (1) 3D retinal organoid technology and (2) directed differentiation of stem cell derived microglia. Given the involvement of microglia in a host of neurodegenerative disorders this project is highly appropriate to elucidate the mechanisms of both LCA and AD. Not only will these studies lead to new insights into the biology of RD disease, but it could also provide a model to explore new therapeutics targeting microglia which would expand the scope of our work from narrowly focused retinal studies to more broadly applicable studies of neurodegenerative disorders like Alzheimer’s disease and LCA.