miR-214-3p attenuates ferroptosis-induced cellular damage in a mouse model of diabetic retinopathy through the p53/SLC7A11/GPX4 axis

Ferroptosis has been implicated in the development of diabetic retinopathy (DR). This study aimed to identify novel ferroptosis-related regulators involved in the pathophysiology of DR using an in vivo streptozotocin (STZ)-induced diabetic model in C57BL/6J mice and cultured primary human retinal vascular endothelial cells (HRECs). Transmission electron microscopy revealed mitochondrial morphological changes consistent with ferroptosis in vascular endothelial cells from STZ-treated mice. Western blot analysis showed increased levels of ferroptosis markers (4-HNE, p53, phosphorylated p53) along with decreased levels of glutathione (GSH), SLC7A11, and GPX4 in diabetic mice. In vitro experiments demonstrated that ferroptosis inhibitors, including pifithrin-α (a p53 inhibitor) and ferrostatin-1 (Fer-1), mitigated cellular damage and Fe²⁺ accumulation in high-glucose-treated HRECs. These inhibitors also improved mitochondrial membrane potential and restored GSH levels. Bioinformatics analysis and dual-luciferase assays identified a p53 binding site within the miR-214-3p sequence. Overexpression of miR-214-3p in high-glucose-treated HRECs resulted in downregulation of p53 and upregulation of SLC7A11 and GPX4, thereby alleviating ferroptosis-induced injury. This study demonstrates that ferroptosis contributes to retinal damage at tissue, cellular, and molecular levels in DR. Specifically, p53, regulated by miR-214-3p, promotes ferroptosis through the SLC7A11/GPX4 pathway under high-glucose conditions. These findings suggest that the miR-214-3p/p53/SLC7A11/GPX4 axis could serve as a potential therapeutic target for managing ferroptosis and retinal damage in diabetic retinopathy.