Abstract
Purpose:
Human induced pluripotent stem cells (hiPSCs) have the potential to differentiate into any cell type of the body, providing a unique tool for cell replacement, disease modeling, and drug screening. To serve in this capacity, however, hiPSCs must be directed to properly differentiate to the cell type of interest. We have previously demonstrated the ability to differentiate hiPSCs to a retinal lineage. However, the ability to derive retinal ganglion cells (RGCs) from hiPSCs has been largely ignored to date. Such an ability would not only serve as a novel model of human retinogenesis, but would also have profound implications for diseases such as glaucoma or other optic neuropathies.
Methods:
hiPSCs were induced to differentiate toward a retinal lineage following previously established protocols. hiPSC-derived retinal cells were then characterized for their ability to generate RGC phenotypes, including those cells expressing the RGC-specific transcription factors BRN3 and Islet-1. The developmental process underlying this RGC differentiation was further analyzed by immunocytochemistry and RT-PCR analysis, and RGCs derived in this fashion were examined for the expression of other expected RGC characteristics.
Results:
Within the first 40 days of differentiation, RGCs were readily identifiable within differentiating cultures of hiPSCs based on their progression through a CHX10-positive retinal progenitor intermediary as well as their later adoption of the RGC-specific transcription factor BRN3. Further characterization of these cells revealed numerous characteristics of RGCs, including the expression of MATH5, PAX6, and Islet-1. Additionally, treatment of these cells with intrinsic and/or extrinsic factors known to influence RGC development enhanced specification of these cells from a more primitive retinal progenitor cell fate.
Conclusions:
The data presented within this study demonstrates the ability of hiPSCs to serve as a reliable source of patient-derived RGCs. Development of these cells has been examined and shown to proceed through predicted developmental stages, yielding a more mature RGC population possessing many RGC-associated characteristics. These results will allow for future studies in which these hiPSC-derived cells may be utilized for studies of a variety of optic neuropathies afflicting the retinal ganglion cell population.
Keywords: 721 stem cells •
531 ganglion cells •
500 differentiation