Small Nucleolar RNAs in Pseudoexfoliation Glaucoma

Abstract

Small nucleolar RNAs (snoRNAs) are small non-coding regulatory RNAs that have been investigated extensively in recent years. However, the relationship between snoRNA and glaucoma is still unknown. This study aims to analyze the levels of snoRNA expression in the aqueous humor (AH) of patients with pseudoexfoliation glaucoma (PEXG) compared to a control group and identify hypothetical snoRNA-dependent mechanisms contributing to PEXG. The AH was obtained from eighteen Caucasian patients, comprising nine PEXG and nine age-matched control patients. RNA was isolated, and a microarray system was used to determine the snoRNA expression profiles. Functional and enrichment analyses were performed. We identified seven snoRNAs, SNORD73B, SNORD58A, SNORD56, SNORA77, SNORA72, SNORA64, and SNORA32, in the AH of the PEXG and control group patients. Five snoRNAs showed statistically significantly lower expression in the PEXG group, and two snoRNAs had statistically significantly higher expression in the PEXG group compared to the control group. In addition, we identified two factors-CACNB3 for SNORA64 and TMEM63C for SNORA32, similar to PEX-related genes (CACNA1A and TMEM136). The enrichment analysis for four genes targeted by snoRNAs revealed possible mechanisms associated with glaucoma and/or PEX, but the direct role of snoRNAs in these biological processes was not proven.

Keywords: PEX; PEXG; aqueous humor; pseudoexfoliation glaucoma; pseudoexfoliation syndrome; small nucleolar RNA; snoRNA.

Figure 1

Lower snoRNA expression in the PEXG group compared to the cataract group. Data are shown as mean [log2].

Figure 2

Higher snoRNA expression in the PEXG group compared to the cataract group. Data are shown as mean [log2].

Figure 3

Cluster analysis results based on the expression levels of the detected snoRNAs.

Figure 4

Terms of the Gene Ontology (GO): Biological Processing (GO:BP), GO: Cellular Compartment (GO:CC), GO: Molecular Function (GO:MF), and REACTOME categories, revealed for glaucoma- and/or pseudoexfoliation syndrome (PEX)-associated genes targeted by snoRNAs found in the current study in the aqueous humor (AH) of patients with PEXG and age-matched controls. p-value—EASE score for enrichment adjusted by the Benjamini correction for multiple-hypothesis testing. The number in brackets following the names of terms indicates the number of associated genes. The plot was generated using the ggplot2 3.3.0 package in R.