DNA Methyltransferase 3A–Dependent Suppression of Hypoxia-Inducible Factor-1α Alleviates Myopia by Reducing Scleral Ferroptosis and Fibroblast Extracellular Matrix Remodeling

Abstract

Hypoxia-inducible factor-1α (HIF-1α) is associated with myopia, but the underlying mechanisms remain unclear. This study investigates the role of HIF-1α in ocular refractive development and its mechanisms. Sprague-Dawley rats were induced with myopia using the form deprivation method, and the expression of HIF-1α was analyzed by Western blot analysis. Oxidative stress levels were assessed by measuring reactive oxygen species, superoxide dismutase, and malondialdehyde. Additionally, the protein expression of glutathione peroxidase 4 (GPX4) and solute carrier family 7 member 11 (SLC7A11/xCT) was evaluated using Western blot analysis and immunohistochemistry, and extracellular matrix remodeling was assessed by measuring matrix metalloproteinase 2 (MMP2), tissue inhibitor of MMP2 (TIMP2), α-smooth muscle actin (α-SMA), and collagen 1α1 (COL1A1). Results showed that HIF-1α expression was significantly up-regulated in form deprivation-induced myopic rats, with increased levels of oxidative stress and ferroptosis. In fibroblast cells under low oxygen conditions, MMP2 and α-SMA levels increased, whereas TIMP2 and COL1A1 levels decreased. Transfection with shRNA targeting HIF1A (sh-HIF1A) lentivirus elevated GPX4 and xCT expression, and HIF-1α knockdown reduced MMP2 and α-SMA expression while increasing TIMP2 and COL1A1 expression. However, erastin restored their levels. Furthermore, DNA methyltransferase 3A suppressed HIF-1α expression by promoting its promoter methylation. In conclusion, hypoxia-induced HIF-1α expression promotes ferroptosis and extracellular matrix remodeling, contributing to the pathogenesis of myopia. DNA methyltransferase 3A may reduce HIF-1α expression through methylation, positioning it as a potential target for myopia therapy.