Hederagenin ameliorates ferroptosis-induced damage by regulating PPARα/Nrf2/GPX4 signaling pathway in HT22 cells: An in vitro and in silico study

Background: Hederagenin (HG), derived from ivy seeds, is known to offer protection against Alzheimer's disease (AD). However, the specific molecular pathways through which it counters ferroptosis-induced neurotoxicity are not fully elucidated. This investigation seeks to delineate the processes by which HG mitigates neurotoxic effects in HT22 cells subjected to glutamate (Glu)-induced ferroptosis.

Methods: HT22 cell ferroptosis was prompted by Glu exposure. Cell viability was assessed using CCK-8 and LDH assays, while Fe²⁺ fluorescence and assays of iron-related proteins served to gauge intracellular Fe²⁺ concentrations. Evaluations of mitochondrial structure and functionality employed JC-1 staining and transmission electron microscopy. Assessments of ROS, lipid peroxidation, MDA, 4-HNE, and the GSSG/GSH ratio were conducted to ascertain HG's antioxidative efficacy. The expression of proteins within the PPARα/Nrf2/GPX4 pathway was quantified via western blotting, with molecular docking (MD), and molecular dynamics simulations (MDS) used to explore protein interactions.

Results: HG diminished the cellular toxicity triggered by Glu in HT22 cells, lowered Fe²⁺ within cells, and rejuvenated mitochondrial morphology and performance. Concurrently, it modulated proteins critical to Fe²⁺ metabolism, diminished ROS and lipid peroxidation, and elevated GSH/GSSG ratios. Enhanced PPARα/Nrf2/GPX4 protein levels were corroborated by western blot results. Furthermore, molecular docking revealed favorable binding of HG to the proteins PPARα, Nrf2, and GPX4, with binding energies of -7.751, -7.535, and -7.414 kcal/mol, respectively. MDS confirmed robust interactions between HG and these pivotal targets.

Conclusion: The evidence suggests that HG effectively mitigates Glu-induced ferroptosis in HT22 cells by activating the PPARα/Nrf2/GPX4 signaling pathway. These findings endorse HG's potential as a nutritional adjunct for AD management.