LCN2 aggravates diabetic cataracts by promoting ferroptosis in lens epithelial cells

Abstract

Abstract Background Cataracts are the leading cause of reversible blindness worldwide. Diabetic cataract (DC), a prevalent complication of diabetes mellitus, is characterized by its high occurrence, rapid progression, and severe impact. The prevalence of diabetes varies greatly between the northern and southern regions, with higher rates observed among northern residents. DC-induced lens opacity is mainly attributed to oxidative stress. However, it remains unclear whether ferroptosis, a form of regulated cell death, occurs in crystalline epithelial cells during the pathogenesis, which may represent a novel mechanism contributing to DC. Methods Transmission electron microscopy, quantitative assays for iron levels and reactive oxygen species (ROS), real-time quantitative polymerase chain reaction (RT-qPCR), western blotting, immunofluorescence, and immunohistochemistry were used to detect ferroptosis. Gene editing techniques were utilized to study the regulatory relationships among lipocalin 2 (LCN2), glutathione peroxidase 4 (GPX4), and ferritin heavy chain (FTH). Local knockdown of the LCN2 gene in B-3 cells and the eyes of Sprague Dawley (SD) rats was performed to verify and further explore the role and regulatory mechanisms of LCN2 in DC-associated ferroptosis. Results An in vitro model using high glucose levels and an in vivo model with streptozotocin-induced diabetes in SD rats were successfully established. Ferroptosis was observed in both in vitro and in vivo experiments. LCN2 protein was normally expressed in human and rat lens epithelial cells, but its expression significantly increased during ferroptosis. The ferroptosis inhibitor, ferrostatin-1 (Fer-1) effectively inhibited ferroptosis and reduced LCN2 protein expression. Notably, local knockdown of LCN2 via gene editing protected lens epithelial cells from ferroptosis in vitro and slowed the progression of DC in SD rats in vivo. Conclusion Our findings underscore the significant role of ferroptosis in the pathogenesis of DC, suggesting that selectively targeting LCN2 activation and enhancing ferroptosis resistance may offer a novel therapeutic approach for treating DC.