Abstract
Purpose :
Pseudoexfoliation (PEX) glaucoma (PEXG) represents a particularly severe and common type of glaucoma. To gain a better understanding of the underlying pathology, we elucidated the PEX-related transcriptomic landscape and biological pathways by employing high-throughput RNA sequencing (RNA-Seq) of different anterior segment tissues derived from PEX and healthy control eyes.
Methods :
Anterior segment tissues, including iris (17 control, 18 PEX/PEXG), ciliary body (20 control, 19 PEX/PEXG), and whole lens (8 control, 8 PEX), were obtained from donor eyes with PEX syndrome/glaucoma and age-matched controls. RNA was subjected to deep bulk RNA sequencing on a HiSeq-2500 platform (Illumina). Differential expression analysis was performed with DESeq2 (v1.28.1). Functional enrichment analysis of the differentially expressed genes (DEGs) was performed with Ingenuity Pathway Analysis, InnateDB and manual annotation. Transcriptomic findings were validated by qPCR and immunohistochemistry.
Results :
RNA-seq revealed significant DEGs (log2+/- 0.5, p-adj < 0.05) 769 in iris, 314 in ciliary body, and 302 in lens specimens of PEX compared to control eyes with several DEGs in common between tissues, but only two DEGs, DUSP2 and G0S2, in common among all three tissues. DUSP2 (dual-specificity phosphatase) is known to be involved in immune and inflammatory processes, whereas G0S2 (G0/G1 switch 2) plays a key role in lipid and fatty acid metabolism. Functional annotation of DEGs and pathway analysis revealed both known (e.g. Extracellular matrix, TGF-ß signaling) and new biological processes, such as cell adhesion, fatty acid metabolism Wnt signaling and SLC-mediated transport as being dysregulated in PEX tissues. Validation experiments confirmed differential expression of cell adhesion molecules, Wnt signaling components, and fatty acids in anterior segment tissues and aqueous humor samples of PEX patients.
Conclusions :
By analyzing three PEX-relevant anterior segment tissues, this study presented ample evidence that abnormalities in cell adhesion, Wnt signaling and fatty acid metabolism are involved in the pathophysiology of PEX syndrome and glaucoma, which may serve as potential targets for the development of novel treatment strategies for this common vision-threatening disease.
This abstract was presented at the 2024 ARVO Annual Meeting, held in Seattle, WA, May 5-9, 2024.