Induction of Rod and Cone Photoreceptor-Specific Progenitors from Stem Cells.

Retinal degeneration includes a variety of diseases for which there is no regenerative therapy. Cellular transplantation is one potential approach for future therapy for retinal degeneration, and stem cells have emerged as a promising source for future cell therapeutics. One major barrier to therapy is the ability to specify individual photoreceptor lineages from a variety of stem cell sources. In this review, we focus on photoreceptor genesis from progenitor populations in the developing embryo and how this understanding has given us the tools to manipulate cultures to specific unique rod and cone lineages from adult stem cell populations. We discuss experiments and evidence uncovering the lineage mechanisms at play in the establishment of fate-specific rod and cone photoreceptor progenitors. This may lead to an improved understanding of retinal development in vivo, as well as new cell sources for transplantation.