Inhibition of Cyclooxygenase-2 Upregulates the Nuclear Factor Erythroid 2-related Factor 2 Signaling Pathway to Mitigate Hepatocyte Ferroptosis in Chronic Liver Injury.

Abstract

Background and aims: Ferroptosis plays an essential role in chronic liver diseases, and cyclooxygenase-2 (COX-2) affects liver fibrosis through multiple mechanisms. However, research on COX-2 regulation of ferroptosis in chronic liver injury remains limited. This study aimed to investigate whether and how COX-2 regulates ferroptosis in chronic liver injury.

Methods: In vivo, a thioacetamide (TAA)-induced chronic liver injury model, characterized by significant liver lipid peroxidation and oxidative stress, was used. COX-2 ^+/+ and COX-2 ^-/- mice were treated with TAA or normal saline. In vitro, primary mouse hepatocytes were isolated and treated with dimethyl sulfoxide (DMSO), erastin+DMSO, etoricoxib+erastin+DMSO, and tBHQ+erastin+DMSO. Mitochondrial morphology, iron metabolism, lipid peroxidation, and oxidative stress were assessed to verify ferroptosis. The nuclear factor erythroid 2-related factor 2 (Nrf2) signaling pathway was measured to investigate the relationship between COX-2 and ferroptosis.

Results: TAA-treated COX-2 ^-/- mice presented milder liver fibrosis, whereas TAA-treated COX-2 ^-/- mice livers and etoricoxib+erastin+DMSO-treated primary hepatocytes exhibited alleviated mitochondrial damage compared with TAA-treated COX-2 ^+/+ littermates and erastin+DMSO-treated primary hepatocytes, respectively. The knockout of COX-2 decreased ferrous ion concentration (p < 0.01) and mitigated lipid peroxidation in TAA-treated livers (p < 0.05). Furthermore, both COX-2 knockout and etoricoxib restored reduced glutathione (p < 0.05) and glutathione peroxidase 4 (p < 0.05), while decreasing malondialdehyde levels (p < 0.05). Additionally, COX-2 inhibition upregulated Nrf2, which helped alleviate erastin+DMSO-induced ferroptosis (p < 0.01).

Conclusions: Ferroptosis contributes to the progression of chronic liver injury. Inhibition of COX-2 upregulates Nrf2, mitigating hepatocyte ferroptosis in chronic liver injury.