Human induced pluripotent stem cells (hiPSCs) provide a unique source of stem cells that have the potential to differentiate into any cell type o the body, including retinal ganglion cells. Furthermore, when derived from a patient's own somatic cells, they have the potential to faithfully serve as a model system of glaucoma. Previously, we have shown the ability to derive various retinal cell types including retinal ganglion cells from hiPSCs. In the current proposal, hiPSCs will be derived from patients with normal-tension primary open angle glaucoma, which would constitute a source of cells with a high predisposition to retinal ganglion cell damage. Conversely, wild type hiPSCs will be utilized as a point of comparison which would have a greater resistance to glaucomatous injury. The comparison of retinal ganglion cells derived from these two sources will allow for the identification of factors contributing to glaucoma-related symptoms. To test this hypothesis, retinal ganglion cells derived from both sources will be examined for the accumulation of reactive oxygen species characteristic of a glaucomatous condition, both under control conditions as well as after exposure to environmental stressors such as hydrogen peroxide. Viability of these cells will also be tested through the use of apoptotic assays to identify differences between the two populations. It is expected that such stressors will result in increased apoptotic activity in those cells derived from glaucoma patients compared with those derived from ocular hypertension sources. Additionally, the role of astrocytes in the progression of a glaucomatous phenotype will be tested. Astrocytes will be derived from patient-specific hiPSCs and co-cultured with retinal ganglion cells. Analysis will be performed to determine the extent of astrocyte contribution to the glaucoma disease phenotype. The successful completion of the aims of this proposal will establish patient-specific hiPSC- derived retinal ganglion cells s a valuable model system for studies of glaucoma, and will also serve as a significant basis upon which to design new pharmaceuticals for the treatment of this disease.
The proposed research in this application aims to utilize human induced pluripotent stem cells to elucidate intracellular features of retinal ganglion cells that predispose them to be susceptible to glaucomatous damage. Through the establishment of human induced pluripotent stem cells from patients with low-tension primary open angle glaucoma as well as wild type sources, retinal ganglion cells as well as astrocytes can be derived with which to study such features. A comparison of retinal ganglion cells and astrocytes in co-culture derived from these two patient samples will serve to highlight those aspects of glaucomatous retinal ganglion cells that underlie their predisposition to disease-related damage.
