Differential DNA methylation patterns in human Schlemm's canal endothelial cells with glaucoma

Area of Science:

• Epigenetics
• Ophthalmology
• Cell Biology

Background:

• Schlemm's canal (SC) endothelial cells regulate intraocular pressure (IOP).
• Dysfunction of SC cells is implicated in primary open-angle glaucoma (POAG).
• Epigenetic modifications, such as DNA methylation, may influence SC cell function in glaucoma.

Purpose of the Study:

• To identify differentially methylated CpG sites (DMSs) in primary human SC cells from glaucoma donors compared to normal controls.
• To investigate the role of DNA methylation in the pathogenesis of glaucoma.

Main Methods:

• Genome-wide DNA methylation profiling of seven primary human SC cell strains (2 glaucoma, 5 normal) using Illumina Human Methylation 450 BeadChip.
• Bioinformatic analysis including quantile normalization, differential methylation analysis (p ≤ 1E-5, methylation change ≥ 0.1, FDR ≤ 0.05), and gene annotation.
• Gene Ontology and KEGG pathway analysis to identify enriched biological processes and pathways. Validation of selected DMSs and DMRs.

Main Results:

• Identified 298 significant DMSs, with 221 located within 1 kb of a gene.
• Enrichment of DMSs in pathways related to cell migration, endothelial cell proliferation, cell adhesion, and gap junctions.
• Detected significant differentially methylated regions (DMRs) in glaucoma-associated genes including TBX3, TNXB1, DAXX, and PITX2.

Conclusions:

• This is the first genome-wide DNA methylation profiling study in cultured human SC cells.
• Identified DMSs and DMRs in pathways and genes relevant to glaucoma pathogenesis and aqueous humor outflow.
• Provides insights into the epigenetic mechanisms underlying glaucoma development and SC cell dysfunction.