Homocysteine induces ferroptosis in renal tubular epithelial cells via β-catenin/GPX4 signaling pathway.

Hyperhomocysteinemia can cause severe damage to kidney. Ferroptosis represents a critical mechanism in the initiation and development of kidney disorders. We focus on the β-catenin/GPX4 signaling pathway to explore how homocysteine influences ferroptosis regulation in renal tubular epithelial cells. C57BL/6J mice were administered drinking water with high level of homocysteine to establish a hyperhomocysteinemia model. In the cell experiments, HKC-8 cells were exposed to homocysteine for a duration of 12 h. Active β-catenin, β-catenin, GPX4, FTH1, and KIM-1 were detected using Western blotting; Biochemical assays were conducted to measure lipid ROS, Fe(2+), and GSH; GPX4 and β-catenin were detected through immunohistochemistry and immunofluorescence techniques; Mitochondrial damage was examined using transmission electron microscopy; ChIP analysis, coupled with dual-luciferase reporter gene assays, was employed to investigate the relationship between β-catenin protein and GPX4 gene promoter. Our findings revealed that homocysteine disrupted β-catenin signaling, inhibited GPX4 expression in renal tubular epithelial cells, subsequently promoted ferroptosis. Overexpression of β-catenin or GPX4 inhibited ferroptosis induced by homocysteine, and β-catenin regulated GPX4 expression in renal tubular epithelial cells. Further assays demonstrated that GPX4 acted as a target gene of β-catenin. In conclusion, homocysteine elicits ferroptosis in renal tubular epithelial cells by disrupting β-catenin signaling and inhibiting its target gene, GPX4.