Histone H3 lysine 9 tri-methylation is associated with pterygium

Background: Pterygium, abnormal growths of conjunctival tissue onto the cornea, are common ocular surface conditions with a high risk of recurrence after surgery and potential ophthalmic complications. The exact cause of pterygium remains unclear, and the triggers are still unknown. This study aims to investigate the relationship between pterygium and epigenetics to uncover the cause of pterygium and identify biomarkers for its diagnosis. Methods: We performed a ChIP-seq assay to compare genome-wide histone modification levels between normal conjunctiva and stage 3 pterygium samples. Results: In this study, we investigate the epigenetic profiles of patients with pterygium, focusing on histone H3 lysine 4 (H3K4) and lysine 9 (H3K9) trimethylation (me3). While H3K4me3 levels showed no significant genome-wide change, they were significantly altered in genes related to development and ocular diseases. Conversely, H3K9me3 levels were markedly elevated genome-wide, particularly at the promoters of 82 genes involved in developmental pathways. Furthermore, we identify six genes, ANK2, AOAH, CBLN2, CDH8, CNTNAP4, and DPP6, with decreased gene expression correlated with substantially increased H3K9me3, suggesting their potential as biomarkers for pterygium. Conclusion: This study represents the first report linking histone modification to pterygium progression, providing valuable insights into therapeutic strategies and potential drug targets.