Abstract
Purpose::
Retinitis pigmentosa (RP) is the most common form of hereditary retinal degeneration, with a prevalence of about 1:4000. To better elucidate the pathogenetic bases of RP, it is essential to gain detailed information about the expression of RP genes in the human retina. Unfortunately, to date, little information is available on expression patterns in the human retina of RP genes at the cellular level and the current knowledge is inferred through the analysis of the mouse. To overcome this lack of information, we decided to generate an expression atlas of the 34 known genes responsible for RP in both human and murine eyes.
Methods::
We retrieved appropriate templates for 34 genes responsible for Retinitis pigmentosa and we used them to perform RNA in situ hybridization (ISH) studies on human and murine adult eye cryosections.
Results::
The majority of the analyzed RP genes showed similar expression patterns between human and mouse adult retina. Of notice is that expression patterns of a subset of human RP genes significantly differ from their mouse orthologs. The most interesting differences were observed in the expression patterns of genes known to be involved in the visual cycle process. LRAT, RPE65, RLBP1 and RGR genes show significant differences in the expression between human and mice. Interestingly, some of these genes do not have a uniform expression pattern throughout human retina. Precisely, higher levels of expression were observed in the central part of the retina, as compared with the peripheral part. This differential mRNA distribution may reflect the differences between mouse and human retinas, and in particular the presence of the macular area in the human eye.
Conclusions::
We generated a comprehensive expression atlas of genes involved in RP and carried out a detailed comparative analysis of gene expression in adult retina between human and mouse. This atlas will be a valuable tool to acquire novel hints on the putative function of some RP genes in the human retina and to translate research performed in the murine models of RP to humans.
Keywords: degenerations/dystrophies • gene/expression • in situ hybridization