Nrl Gene Can Sufficiently Reprogram Retinal Stem Cells Into Photoreceptor

Abstract

Purpose: : To examine temporal and spatial expression of retina leucine zipper (Nrl) gene, and to assess its ability to reprogram retinal stem cells (RSCs) that can commit themselves toward the photoreceptor fate in vitro and in vitro.

Methods: : RSCs were isolated from the neural retina of GFP-C57 mice. Brifely, the peripheral retina and the optic nerve stalk were removed. The retina was dissected and digested for 10 minutes at 37°C in papain enzyme solutions. Overexpression of Nrl was mediated by lentiviral transduction. Photoreceptor differentiation was evaluated by RT-PCR and immunocytochemical analysis. Subretinal transplantation was performed. A 33-gauge needle (Hamilton, Switzerland) was inserted through the sclera into the sub-retinal space, and 2 µl cell suspension was slowly injected for adult mice to produce a local retinal detachment in the superior and/or inferior hemisphere. The transplantation efficiency of RSCs was examined for their survival, integration and differentiation into retinal cells.

Results: : During spontaneous differentiation, RSCs expressed cell type-specific markers of all retinal neurons and glia cells. In contrast, after transduction by Nrl gene, a subpopulation of differentiated cells was identified to be committed to the photoreceptor lineage because these cells expressed rod-cell specific markers. Nrl transducted RSCs transplanted into adult retina were capable of integrating into the outer nuclear layer and differentiating into new photoreceptors.

Conclusions: : Our preliminary data suggest that Nrl is required for rod photoreceptor differentiation and is sufficient for reprogramming adult RSCs into rod photoreceptors.

Keywords: gene transfer/gene therapy • photoreceptors • retina