Regeneration of human RPE cells from autologous urine-derived iPS cells - PROJECT SUMMARY Age-related macular degeneration (AMD) is the most common cause of irreversible visual impairment in the US, and restoring retinal function in AMD patients remains a big challenge. Retinal pigment epithelium (RPE) degeneration is the hallmark of advanced “dry” or non-neovascular AMD with no treatment available. The implanted retinal pigment epithelial cells (RPEs) or a patch of RPE, generated from induced pluripotent stem cells (iPSCs), provide great potential in the treatment of AMD. Autologous iPSCs possess therapeutic potential with less immunogenicity and have less ethical controversy than human embryonic stem cells-based therapies. Two phases are required from somatic cells to generate mature RPEs: iPSCs are reprogrammed from different somatic cell sources located at peripheral blood, skin, or other epithelial tissues, and then iPSCs are guided to differentiate to functional RPEs (RPEsiPSC). Despite current progress in generating RPEs from somatic cells, several barriers remain in their clinical application, and there is an urgent need to develop an optimized strategy with higher efficiency and rapid differentiation kinetics in the generation of RPEsiPSC. Human primary USCs, as renal progenitors first discovered by the PI’s team, are easily accessible and possess robust cell proliferation and renewal capacity for tissue regeneration. Our previous studies demonstrated that iPSCs reprogrammed from USC (u-iPSCs) more efficiently and rapidly than iPSC from other cell sources. u-iPSC efficiently differentiated into neurocytes, but RPEsu-iPSC have not been developed yet. The long-term goal of this proposal is to use RPEs generated from autologous USC-derived iPSCs (RPEsu-iPSC) to reestablish the interaction with photo‑receptors and prevent degeneration of the retina, restoring the vision function for patients with AMD. The overall objective of this R21 study is to generate pure RPEs from u-iPSC (RPEsu-iPSC). Our central hypothesis is that u-iPSC reprogrammed from USC (epithelial progentior cells) are more efficiently and rapidly differentiated into mature RPEs (epithelalial lineage cell) with specific makers and durable tight junction, compared to iPSC from mesenchymal cell lineages (i.e, skin fibroblasts and blood mononuclear cells). Thus, the specific aim of this study is to develop and optimize a strategy for generating reliably archived human RPEsu-iPSC. We will determine the efficiency of RPE differentiation from u-iPSCs and assess the function of RPEsu-iPSC compared to that of iPSC from skin and blood cells, with adult human primary RPE as a control. We expect that USC obtained non-invasively from AMD patients could be an optimal cell source for generating mature RPEsu-iPSC in a cost-effective manner for personalized medicine in the treatment of AMD. This in vitro differentiated human RPEsu-iPSC will be highly valuable and pave the ground for a future R01 proposal on an in vivo study with autologous RPEsu-iPSC. The broader impact is that RPEsu-iPSC might be used for RPE research, in vitro ocular disease modeling, and toxicity testing. An in vitro model of RPEsu-iPSC might provide a superior platform for personalized drug discovery compared to existing human RPE cell lines or animal cell sources.
