Abstract
Abstract: :
During the AMD disease process phenotypic changes can be observed in a number of retinal cells, especially in the retinal pigment epithelium (RPE) and photoreceptor cells. These phenotypic changes reflect variations in the expression of related genes. Following this rationale, changes in the expression level of a gene are indicative of the involvement of a gene in a disease pathway, and thus expression changes can be used to identify genes involved in the pathogenesis of AMD. Purpose: The objective of this study is to gain insight into the expression of genes in tissues predominantly affected by age related macula degeneration; the RPE/choroids and neural retina. Methods: RPE/Choroid and neural retinas have been isolated from human donor eyes from various ages. Genome-wide expression profiling is being carried out using oligonucleotide microarrays containing 22.000 features (Agilent Technologies Inc.) representing approximately 15.000 different genes. This set contains all well-known genes (13.000 Unigene clusters) as well as a selection of ESTs with unknown function. The microarrays are hybridized with cRNA of RPE/Choroid and retinas from healthy controls of different ages. As the disease predominantly affects the photoreceptor cells and RPE cells, laser dissection microscopy is currently being employed in order to isolate these cell types specifically. Results: From the first hybridization results detailed information regarding the expression of a large number of genes in these specialized tissues has been obtained. In RPE/choroid a set of 2500 genes is abundantly expressed, and for 300 of these genes (12%) the function is currently unknown. For at least 80% of these genes genomic mapping information is available, thereby resulting in a pool of candidate genes for genetic retinal degenerations. Currently additional hybridizations are being carried out, that will enable comparisons between the different tissues, and specific cell types, thereby identifying a distinct set of RPE cell of photoreceptor cells specific genes. Conclusion: This experiments illustrates the wealth of valuable data a limited microarray experiment already yields, while a large scale gene-expression profiling is being prepared. Furthermore, the set of data from "healthy" donors function as a reference to which different diseased samples will be compared.
Keywords: 308 age-related macular degeneration • 417 gene/expression • 418 gene mapping