An in vitro mouse model for retinal ganglion cell replacement therapy using eye-like structures differentiated from ES cells

The aim of this study was to investigate the developmental potential of embryonic stem (ES) cell-derived eye-like structures as a replacement cell therapy model for retinas with N-methyl-d-aspartate (NMDA)-induced damage. For this purpose mouse ES cells were induced to differentiate into eye-like structures in vitro for 10 days and co-cultured with adult mouse retina treated with or without NMDA treatment. NMDA induces excitotoxic neuronal cell death in the inner neural retina, specifically within the ganglion cell layer. After 10 days of co-culture, the specimens were fixed, embedded in paraffin wax and analyzed by immunohistochemistry. Transplanted eye-like structures differentiate into Tuj1-positive neurons when co-cultured with an adult mouse retina and the cells then migrate into the ganglion cell layer. When co-cultured with an NMDA-treated retina, most of the cells migrating into the ganglion cell layer express the ganglion cell-specific markers Hu and Brn3b. Murine ES cell-derived eye-like structures contain cell populations that can differentiate into ganglion-like cells in the host ganglion cell layer in vitro. Moreover, their contribution to the ganglion cell layer was more prominent when ganglion cell specific damage was induced by NMDA administration. These findings suggest that cells prepared from the eye-like structures generated from ES cells may be useful for cell replacement therapy and may also serve as a model system for such therapies.