Abstract
Purpose:
Retinal progenitor cells alter their properties according to the time axis of development and sequentially produce different subpopulations of retinal cells. We had previously found that early and late retinal progenitor cell populations are labeled by different surface antigens SSEA-1 and c-kit, respectively. To characterize stage specific retinal progenitor cells, we examined transcriptome of SSEA-1 positive cell at E14, c-kit positive cells at P1, and c-kit negative cells at P1, by DNA microarray analysis. By comparison of data, we choose genes specifically expressed in c-kit positive late retinal progenitor cells, and characterize these genes.
Methods:
We examined effects of gain- and loss-of-Notch signaling for expression of these genes and to delineate involvement of the genes for Mueller glia genesis. Loss-of-function analysis of the genes was performed using RNA interference gene transfer into retinal explant cultures.
Results:
We chose 22 genes specifically expressed in late retinal progenitor cells, and the list contains Sox8, Rlbp1, and Hey2, which had been previously reported to be involved in glial development in retina. We overexpressed NICD in retinal explants, and expression level of more than half of the genes was up-regulated, and expression of most of candidate genes except for CD9, Mcam, and Arhgef3 were suppressed in the presence of DAPT. These results indicate that candidate genes were positively affected by Notch signaling. Loss-of-function analysis reveal that number of GS-positive Müller glia decreased significantly in samples expressing shRNA.Therefore it was suggested that these genes may play important roles for Müller glia differentiation.
Conclusions:
c-kit positive retinal progenitor cells at P1 contains Müller glia precursor cells, resulting enrichment of genes related to glial differentiation at this stage of retinal progenitors. We propose that analysis of purified subset of retinal cells is a powerful tool to analyze molecular basis of retinal development.
Keywords: 698 retinal development •
535 gene microarray •
603 Muller cells