An Investigation of Global Gene Expression Patterns in Glaucoma and Ocular Hypertension Derived Optic Nerve Heads

ABSTRACT: Purpose: The optic nerve head (ONH) is the likely site of initial damage in the glaucomatous eye. Despite the recognition of elevated intraocular pressure (IOP) as a leading risk factor for the development of glaucoma, ocular hypertension (OHT) eyes displaying consistently elevated IOP do not experience ONH damage. This study aims to identify global gene expression variations in glaucomatous ONHs and their relationship to those identified in OHT derived ONHs in order to improve our understanding of IOP-induced ONH damage. Methods: (N=6) ONHs were collected from clinically confirmed glaucoma, OHT and age-matched control donor eyes. Total RNA extracted from ONHs was reverse transcribed and assayed using the Affymetrix Human Exon 1.0 ST array. Differentially expressed genes in glaucoma versus control and OHT derived ONHs were identified using an ANOVA analysis with a 1.25 fold change limit and P-value < 0.05. Quantitative RT-PCR was performed to validate selected differentially expressed genes. Results: Microarray analysis revealed 149 under under-expressed genes in POAG versus control ONHs, many of which are involved in ion transport, axonogenesis and macromolecule catabolic processes. 297 genes were over expressed in OHT versus glaucoma derived ONHs. Mediators of oxidation-reduction and chemical homeostasis were among the most prominent gene groups identified. The over expression of prostaglandin-endoperoxide synthase 2, integrin, beta-like 1 and fibulin 5 in glaucomatous ONHs was confirmed by qRT-PCR. Conclusions: Our data demonstrates marked alteration in global gene expression patterns in the glaucomatous ONH, likely due to extensive tissue injury. The observed overlapping of several differentially expressed genes in glaucoma and OHT derived ONHs suggests the induction of common mechanisms in response to elevated IOP. Preferential over-expression of certain gene groups in OHT but not glaucoma derived ONHs may confer possible protection against IOP-induced ONH damage, which remains to be investigated in future studies. (N=6) Glaucoma, ocular hypertension and age-matched control ONHs were assayed to investigate and compare global gene expression patterns in each sample group.

ORGANISM(S): Homo sapiens

SUBMITTER: Dina Ahram 

PROVIDER: E-GEOD-45570 | biostudies-arrayexpress |

REPOSITORIES: biostudies-arrayexpress