Derivation of Traceable and Transplantable Photoreceptors from Mouse Embryonic Stem Cells

• De novo isolation of Crx-GFP embryonic stem cell lines to trace photoreceptors
• 3D culture system fine-tuning to generate many integration-competent photoreceptors
• Revealing in-vitro- and in-vivo-developing retina similarities
• Characterization of the most appropriate stage to transplant photoreceptors

SummaryRetinal degenerative diseases resulting in the loss of photoreceptors are one of the major causes of blindness. Photoreceptor replacement therapy is a promising treatment because the transplantation of retina-derived photoreceptors can be applied now to different murine retinopathies to restore visual function. To have an unlimited source of photoreceptors, we derived a transgenic embryonic stem cell (ESC) line in which the Crx-GFP transgene is expressed in photoreceptors and assessed the capacity of a 3D culture protocol to produce integration-competent photoreceptors. This culture system allows the production of a large number of photoreceptors recapitulating the in vivo development. After transplantation, integrated cells showed the typical morphology of mature rods bearing external segments and ribbon synapses. We conclude that a 3D protocol coupled with ESCs provides a safe and renewable source of photoreceptors displaying a development and transplantation competence comparable to photoreceptors from age-matched retinas.