Abstract
Purpose: :
Recently it was reported that rod photoreceptor precursors at a specific ontogenetic stage expressing the transcription factor Nrl were able to integrate, differentiate into rod photoreceptors, and form functional synaptic connections with the host retina with restoration of visual function after subretinal transplantation. Herein we determine if we can induce in vitro expression of Nrl in retinal progenitors derived from hESC.
Methods: :
hESCs were cultured on mouse PA6 stromal cells in differentiation medium (Kawasaki H, Neuron 2000). Cells were examined with immunocytochemistry for rod photoreceptor precursor marker Nrl, as well as various neuron markers as β-tubullin III, MAP-2, Neurofilament 200 (NF200), GFAP, retinal progenitor marker PAX6 and synaptic proteins markers such as synaptophysin or vesicular glutamate transporter (vGLUT1). DNA microarray analysis was used to compare the gene expression profiles of hESC cultured on mouse fibroblasts or neural progenitors on PA6 cells to the transcriptome of the adult neural retina.
Results: :
Neural progenitor cells obtained after culturing hESC on PA6 cells expressed the rod photoreceptor precursor marker Nrl, in addition to retinal progenitor marker Pax-6, and neuron markers β-tubullin III, MAP-2, NF200, astrocyte marker GFAP and the synaptic vesicle proteins. Hierarchical clustering analysis of samples suggested that hESC cultured on PA6 stromal cells exhibited gene expression characteristics towards differentiating into neural retina.
Conclusions: :
hESCs can be induced to express the photoreceptor transcription factor protein Nrl, in addition to other neuronal and synaptic markers, indicating that they have differentiated into retinal progenitor cells. Further study is needed to determine the optimal conditions for differentiation of hESC and subsequent transplantation in the treatment of animal models of retinal degeneration.
Keywords: gene microarray • transcription factors