Profiling IOP-responsive genes in anterior and posterior ocular tissues in the rat CEI glaucoma model

• Published in: bioRxiv
• Main Authors: Lozano, Diana C, Yang, Yong-Feng, Cepurna, William O, Smoody, Barbara F, Ing, Eliesa, Morrison, John C, Keller, Kate E
• Format: Journal Article Paper
• Language: English
• Published: United States Cold Spring Harbor Laboratory 11.02.2024
• Edition: 1.1
• Subjects: Molecular Biology; intraocular pressure; optic nerve head; glaucoma; gene expression; trabecular meshwork
• ISSN: 2692-8205; 2692-8205
• DOI: 10.1101/2024.02.11.579818

The rat Controlled Elevation of Intraocular pressure (CEI) model allows study of responses to defined intraocular pressures (IOP). In this study, we use Nanostring technology to investigate IOP-related gene responses in the trabecular meshwork (TM) and optic nerve head (ONH) simultaneously from the same animals. Male and female rats (N=35) were subject to CEI for 8-hours at pressures simulating mean, daytime normotensive rat IOP (CEI-20), or 2.5x IOP (CEI-50). Naïve animals, receiving no anesthesia or surgical interventions, served as controls. Immediately after CEI, TM and ONH tissues were dissected, RNA isolated, and samples were analyzed with a Nanostring panel containing 770 genes. Post-processing, raw count data were uploaded to Rosalind® for differential gene expression analyses. For the TM, 45 IOP-related genes were significant in the "CEI-50 vs. CEI-20" and "CEI-50 vs. naïve" comparisons, with 15 genes common to both comparisons. Bioinformatics analysis identified Notch and TGFβ pathways to be the most up- and down-regulated KEGG pathways, respectively. For ONH, 22 significantly regulated genes were identified in the "CEI-50 vs. naïve" comparison. Pathway analysis identified 'defense response' and 'immune response' as two significantly upregulated biological process pathways. This study demonstrates the ability to assay IOP-responsive genes in both TM and ONH tissues simultaneously. In the TM, downregulation of TGFβ pathway genes suggest that TM responses may prevent TGFβ-induced extracellular matrix synthesis. For ONH, the initial response to elevated IOP may be protective, with astrocytes playing a key role in these gene responses.