GSK-3β-dependent Nrf2 antioxidant response modulates ferroptosis of lens epithelial cells in age-related cataract

Oxidative stress-induced lens epithelial cells (LECs) death plays a pivotal role in age-related cataract (ARC) with severe visual impairment, in which ferroptosis is gradually receiving numerous attention resulting from lipid peroxide accumulation and reactive oxygen species (ROS) overproduction. However, the essential pathogenic factors and the targeted medical strategies still remain skeptical and indistinct. In this work, by transmission electron microscopy (TEM) analysis, the major pathological courses in the LECs of ARC patients have been identified as ferroptosis, which was manifested with remarkable mitochondrial alterations, and similar results were found in aged mice (24-month-old). Furthermore, the primary pathological processes in the NaIO3-induced mice and HLE-B3 cell model have also been verified to be ferroptosis with an irreplaceable function of Nrf2, proved by the increased sensitivity to ferroptosis when Nrf2 was blocked in Nrf2-KO mice and si-Nrf2-treated HLE-B3 cells. Importantly, it has been found that an increased expression of GSK-30 was indicated in lowNrf2-expressed tissues and cells. Subsequently, the contributions of abnormal GSK-30 expression to NaIO3induced mice and HLE-B3 cell model were further evaluated, inhibition of GSK-30 utilizing SB216763 significantly alleviated LECs ferroptosis with less iron accumulation and ROS generation, as well as reversed expression alterations of ferroptosis markers, including GPX4, SLC7A11, SLC40A1, FTH1 and TfR1, in vitro and in vivo. Collectively, our findings conclude that targeting GSK-30/Nrf2 balance might be a promising therapeutic strategy to mitigate LECs ferroptosis and thus probably delay the pathogenesis and development of ARC.

Automated summary

This study identified ferroptosis as a major pathological process in lens epithelial cells (LECs) of age-related cataract (ARC) patients. The essential role of Nrf2 in ferroptosis was verified in mice and cell models. The increased expression of GSK-30 was found in low Nrf2-expressed tissues and cells, and inhibition of GSK-30 alleviated LECs ferroptosis in vitro and in vivo. Targeting GSK-30/Nrf2 balance could be a promising therapeutic strategy for ARC.