Abstract
Purpose: :
The ciliary body (CB) of the eye consists of the non-pigmented (NPE) and pigmented (PE) epithelium and produces the aqueous humor. Aqueous humor is necessary to build up and maintain intra-ocular pressure (IOP). Increased IOP is a major risk factor for the development of primary open angle glaucoma (POAG). Little is known about the molecular machinery and functional properties of the NPE and PE.
Methods: :
We isolated NPE and PE cells from 4 selected healthy human donor eyes using laser dissection microscopy. Next, RNA isolation, amplification, labeling and hybridization against 44k Agilent microarrays were carried out. We selected the genes of the NPE and PE with the highest mean intensity, with a cut of value at 90th percentile or higher. We generated a list of highly and specifically expressed genes of the NPE and PE, which we further analyzed with bioinformatics, using Ingenuity. Correction for multiple testing was performed.
Results: :
Gene expression profiles of the NPE and PE resembled each other, with 3100 genes highly and commonly expressed in both cell layers. There were 240 genes specifically highly expressed in the NPE and 256 in the PE. Further analysis of these specifically genes revealed the following: In the NPE, 15 molecular networks were derived, the first being ‘Skeletal and muscular disorders and cell death’. There were 7 statistical significant biological functions assigned to the NPE. The most significant was ‘Cell cycle’. Analysis of the PE gene set yielded 20 molecular networks. The first was ‘Genetic disorder and ophthalmic disease’. Twenty-one biological functions were statistical significant in the PE. The most significant was ‘Genetic disorder’. Finally, several molecular pathways link to genes or drugs that are associated with POAG.
Conclusions: :
Our data show that the NPE and PE cells of the ciliary body express a large amount of common genes and a minor set of specific different genes, related to the common and different functionalities of these cell layers.
Keywords: ciliary body • gene microarray