Abstract
Purpose :
Many genes have been associated with primary open-angle glaucoma. Knowledge of their ocular expression pattern can help to identify glaucoma pathways and to select targets for intervention. We investigated whether RNA in-situ hybridisation (RNA - ISH) is a convenient and generally applicable method to obtain detailed ocular expression data of glaucoma genes. The technique was tested on four candidate glaucoma genes. These were selected because of relevance for new experimental therapies (Tnf, Tgfβr3) or because data on their ocular expression were particularly scarce (F5 and Dusp1).
Methods :
We made a list of the candidate glaucoma genes reported in genetic studies and compiled a table of their ocular expression using a publicly available microarray dataset (the ocular tissue database). Gene expression is herein specified at the tissue level. To add cellular detail we performed RNA-ISH for Tnf, Tgfβr3, F5 and Dusp1 on eyes of 2-month-old, healthy, pigmented and albino mice (C57BL/6; n=5 and C57BL/6BrdCrHsd-Tyrc albino; n=5).
Results :
Ocular expression of Tnf was generally low. Most remarkable were patches of relatively high Tnf expression in superficial layers of the corneal epithelium. F5 showed a restricted expression pattern with high expression in the non-pigmented ciliary body epithelium and moderate expression in the peripapillary region. In contrast, Tgfβr3 and Dusp1 were ubiquitously expressed.
Conclusions :
RNA-ISH is a suitable technique to localize glaucoma gene expression, adding meaningful cellular detail to existing microarray expression data. For instance, the high expression of F5 in the non-pigmented ciliary body epithelium suggests a role of this gene in aqueous humor dynamics and intraocular pressure elevation. In addition, the ubiquitous expression of Tgfβr3 will have implications for designing TGF-β related glaucoma therapies, e.g. with respect to side effects. In general, detailed ocular expression maps of glaucoma genes will help to identify glaucoma pathways in specific cell types and to select optimal targets for drug development.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.