Critical role of transcriptome-wide m6A methylation in the aqueous humor of patients with pseudoexfoliation glaucoma.

N-methyladenosine (mA) modification is one of the most common types of methylation modifications in eukaryotic mRNA. However, its role in the pathogenesis of pseudoexfoliation glaucoma (PXG) has not yet been reported. To enhance understanding in this regard, we assessed the mA methylome in the aqueous humor of patients with PXG. MeRIP-Seq and RNA-Seq analyses were performed to compare the mA methylomes and gene expression profiles of the aqueous humor of patients with PXG with those of patients with age-related cataract (ARC). Colorimetric mA quantification was performed to detect global mA levels. Quantitative reverse transcription PCR confirmed the expression of mA-related enzymes and mRNAs in both groups. Results showed significantly higher aqueous humor mA levels in the PXG group than in the ARC group. Five mA-related enzymes, including METTL3, YTHDC2, HNRNPA2B1, HNRNPC, and LRPPRC, were significantly up-regulated in PXG specimens. We also observed 9728 mA-modified peaks related to 6126 gene transcripts in the PXG group, with more than 250 genes containing one mA peak (hypomethylated or hypermethylated). The distribution of the mA peaks was enriched in coding sequences and 3'-untranslated regions for both groups. GGAC motif structures were also significantly enriched. Bioinformatics analysis further revealed that mA plays a critical role in extracellular matrix formation and histone deacetylation. Additionally, MMP14, ADAMTSL1, FN1, and HDAC1 showed significant changes in mA methylation and mRNA expression in the PXG group. Therefore, mA methylation may regulate extracellular matrix composition in PXG and METTL3 may be a pivotal regulator of this process. In the future, it would be necessary to investigate MMP14, ADAMTSL1, FN1, and HDAC1, which are potential target genes.