Subchronic exposure to CeCl3 promotes macrophage ferroptosis and atherosclerotic plaque formation by inhibiting the Keap1/Nrf2/GPX4 pathway

Cerium chloride (CeCl₃), a prevalent by-product of rare earth mining, accumulates in the biota and environment of mining regions, including plants, animals, water resources, and air, posing potential health risks to local residents. Atherosclerosis (AS) is the pathological basis of cardiovascular disease. However, the relationship between subchronic CeCl₃ exposure and AS progression, along with the underlying regulatory mechanisms by which CeCl₃ modulates AS, remains unclear. In this study, we first demonstrated confirmed that CeCl₃ significantly exacerbated AS plaque formation in ApoE^−/− mice fed with high-fat diet (HFD). Moreover, CeCl₃ elevated serum levels of triglycerides (TG), cholesterol (CHO), and low-density lipoprotein (LDL). Further studies showed that CeCl₃ significantly inhibited the expression of key regulators of ferroptosis, such as GPX4 and FTH1, as well as antioxidant enzyme glutathione peroxidase 4 (GPx4) and superoxide dismutase (SOD), and upregulated the levels of lipid peroxidation markers, including reactive oxygen species (ROS), malondialdehyde (MDA), and ferrous iron (Fe²⁺). Besides, CeCl₃ significantly inhibited the expression of Nrf2, NQO1, and HO-1, and impeded Nrf2 nuclear translocation. Mechanistically, CeCl₃ significantly promoted the formation of the Keap1/Nrf2 complex, leading to ubiquitin-mediated Nrf2 degradation. Pharmacological activation of Nrf2 by NK-252 significantly reduced CeCl₃-induced inhibition of GPX4 and FTH1 expression, and reversed its pro-atherosclerotic effects. Dual-luciferase reporter assays confirmed Nrf2 as a transcriptional regulator of GPX4. Taken together, our study demonstrates that CeCl₃ exacerbates HFD-induced AS plaque formation and promotes ferroptosis in macrophages via the Keap1/Nrf2/GPX4 signaling pathway, providing new insights into strategies for preventing cardiovascular diseases with subchronic exposure to CeCl₃.