Protein arginine methyltransferase 1 stimulates basal cell proliferation and migration to maintain corneal epithelial homeostasis

The corneal epithelium is a constantly self-renewing, stratified squamous tissue that protects the inner eye from external stimuli. The organization of the corneal epithelium involves multiple biological activities, including basal cell proliferation and centripetal migration. However, the underlying molecular mechanisms remain unclear. Herein, we identify protein arginine methyltransferase 1 (PRMT1) as a key regulator of corneal epithelial homeostasis. We exploited an inducible Prmt1 knockout mouse model and observed apparent disruption in the corneal epithelial homeostasis. PRMT1-deficient mice exhibited significant corneal epithelial thinning, as evidenced by histological and immunofluorescence staining with epithelium-specific markers. Further investigation showed that the epithelial thinning in these mice resulted from the dysfunction of basal cells. Immunostaining and 5-ethynyl-2'-deoxyuridine incorporation assays demonstrated that PRMT1 depletion significantly inhibited the proliferation and migration of basal cells, whereas no apparent apoptosis-related abnormalities were observed in these cells. Moreover, scratch wound healing assays revealed that knockdown of PRMT1 expression or inhibition of its catalytic activity significantly impaired the migration of corneal epithelial cells. Overall, our findings uncover a critical role for PRMT1 in controlling basal cell proliferation and migration to maintain corneal epithelial homeostasis, thereby providing potential therapeutic targets for the treatment of corneal diseases.