Recently, ferroptosis has been found as a kind of cell death defined by the accumulation of reactive oxygen species (ROS) depending on iron and lipid peroxidation. A high-fat diet (HFD) may have the potential to trigger ferroptosis, resulting in liver injury. Apigenin is a natural flavonoid widely present in fruits and vegetables. In the study, we found HFD-fed could increase the iron level (P < 0.05), malondialdehyde (MDA) level (P < 0.01), the expression of acyl-CoA synthetase long-chain family member 4 (ACSL4) and transferrin receptor 1 (TfR1) (P < 0.01), decrease the glutathione (GSH) level, the expression of glutathione peroxidase 4 (GPX4), ferritin heavy chain (FTH) and ferroportin (FPN) in C57BL mice (P < 0.01). Further, conventional morphological hallmarks of ferroptosis were observed using transmission electron microscopy (TEM). However, apigenin treatment eliminated these harmful effects. Similar to in vivo results, we found apigenin could alleviate palmitic acid (PA)-induced ferroptosis in AML12 cells. Further, we found apigenin could promote PA-inhibited mitophagy and decrease intracellular ROS accumulation, thereby restoring PA-induced lysosomal membrane permeabilization (LMP). In the further mechanism study, we added relevant inhibitors. The results showed that apigenin could clear PA-induced damaged mitochondria through mitophagy, and reduce the leakage of free iron ions in lysosomes into the cytoplasm by restoring the permeability of lysosomes. Therefore, apigenin could inhibit ferroptosis induced by HFD and PA via suppressing lysosome iron efflux by reducing LMP and activating mitophagy in mice and AML12 cells.

Elaidic acid (EA) is a typical trans fatty acid (TFA) that emerges during the processing of various fatty foods. In this study, we found that EA induced renal injury with necroptosis. Pretreatment with a ROS inhibitor and a RIPK3 inhibitor alleviated EA-induced necroptosis. The data indicated that EA induced renal necroptosis through ROS/RIPK3/MLKL pathway. In mechanistic studies, we explored how EA induced ROS production. We found EA caused mitochondrial damage by testing MMP, MFN1, VDAC, and FIS1. Further, we also found EA suppressed mitophagy by testing the levels of LC3, p62, PINK1, Parkin, colocalization of LC3 and Mito-Tracker Red. Mitophagy is a process of selective degradation of damaged mitochondria. A large number of damaged mitochondria couldn’t be cleared by mitophagy in time, which increased ROS levels in renal cells. Pretreatment with a mitophagy activator decreased EA-induced ROS levels and mitochondrial damage. Taken together, our data identified that EA induced renal necroptosis by destroying mitochondria and inhibiting mitophagy, thereby activating the ROS/RIPK3/MLKL pathway.