Gene expression changes during retinal development and rod specification
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2015Access:
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Mansergh FC, Carrigan M, Hokamp K, Farrar GJ, Gene expression changes during retinal development and rod specification, Molecular Vision, 21, 2015, 61 - 87Download Item:
mv-v21-61.pdf (PDF) 1.278Mb
Abstract:
Purpose:
Retinitis pigmentosa (RP) typically results from individual mutations in any one of >70 genes that cause rod
photoreceptor cells to degenerate prematurely, eventually resulting in blindness. Gene therapies targeting individual RP
genes have shown efficacy at clinical trial; however, these therapies require the surviving photoreceptor cells to be viable
and functional, and may be economically feasible for only the more commonly mutated genes. An alternative potential
treatment strategy, particularly for late stage disease, may involve stem cell transplants into the photoreceptor layer of
the retina. Rod progenitors from postnatal mouse retinas can be transplanted and can form photoreceptors in recipient
adult retinas; optimal numbers of transplantable cells are obtained from postnatal day 3–5 (P3–5) retinas. These cells
can also be expanded in culture; however, this results in the loss of photoreceptor potential. Gene expression differences
between postnatal retinas, cultured retinal progenitor cells (RPCs), and rod photoreceptor precursors were investigated
to identify gene expression patterns involved in the specification of rod photoreceptors.
Methods:
Microarrays were used to investigate differences in gene expression between cultured RPCs that have lost
photoreceptor potential, P1 retinas, and fresh P5 retinas that contain significant numbers of transplantable photorecep
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tors. Additionally, fluorescence-activated cell sorting (FACS) sorted Rho-eGFP-expressing rod photoreceptor precursors
were compared with Rho-eGFP-negative cells from the same P5 retinas. Differential expression was confirmed with
quantitative polymerase chain reaction (q-PCR).
Results:
Analysis of the microarray data sets, including the use of t-distributed stochastic neighbor embedding (t-SNE)
to identify expression pattern neighbors of key photoreceptor specific genes, resulted in the identification of 636 genes
differentially regulated during rod specification. Forty-four of these genes when mutated have previously been found to
cause retinal disease. Although gene function in other tissues may be known, the retinal function of approximately 61%
of the gene list is as yet undetermined. Many of these genes’ promoters contain binding sites for the key photoreceptor
transcription factors Crx and Nr2e3; moreover, the genomic clustering of differentially regulated genes appears to be
non-random.
Conclusions:
This study aids in understanding gene expression differences between rod photoreceptor progenitors versus
cultured RPCs that have lost photoreceptor potential. The results provide insights into rod photoreceptor development
and should expedite the development of cell-based treatments for RP. Furthermore, the data set includes a large number
of retinopathy genes; less-well-characterized genes within this data set are a resource for those seeking to identify novel
retinopathy genes in patients with RP (GEO accession: GSE59201).
Sponsor
Grant Number
Other
FB\11\FAR (MRCG)
Health Research Board (HRB)
Science Foundation Ireland (SFI)
Author's Homepage:
http://people.tcd.ie/mansergfhttp://people.tcd.ie/gjfarrar
Description:
PUBLISHED
Author: MANSERGH, FIONA; FARRAR, JANE
Type of material:
Journal ArticleCollections:
Series/Report no:
Molecular Vision;21;
Availability:
Full text availableSubject (TCD):
Genes & Society , Neuroscience , Developmental Biology , Genomes, Genomics , Molecular Biology , VisionLicences: