Silencing GADD45B Ameliorates Epilepsy by Inhibiting Ferroptosis and Maintaining Mitochondrial Homeostasis Through the HIF‐1 Signaling Pathway

ABSTRACT Epilepsy is a chronic brain disorder with unclear pathogenesis and no effective biomarkers. This study aims to identify potential biomarkers and elucidate the regulatory pathways in epilepsy. Epilepsy‐associated differentially expressed genes (DEGs) were discovered from the GSE60772, GSE88992, and GSE100202 datasets. Hub genes were determined from a protein–protein interaction (PPI) network, followed by screening of downstream pathways of growth arrest and DNA damage inducible beta (GADD45B). GADD45B was silenced in lithium‐pilocarpine‐induced epileptic rats and glutamate‐treated HT22 cells to investigate its effects on hippocampal neuron injury, ferroptosis, mitochondrial homeostasis, and its downstream signaling pathway. GADD45B as an epilepsy‐associated hub gene was highly expressed in the hippocampal tissues of epileptic rats. Silencing GADD45B in epileptic rats suppressed neuronal injury and death. It also decreased Fe 2+ , malondialdehyde (MDA), 4‐hydroxy‐2‐nonenal (4‐HNE), reactive oxygen species (ROS), and hypoxia‐inducible factor‐1α (HIF‐1α) but increased glutathione (GSH) in epileptic rats and HT22 cells, as well as suppressed acyl‐CoA synthetase long chain family member 4 (ACSL4) expression and increased glutathione peroxidase 4 (GPX4) and solute carrier family 7 member 11 (SLC7A11) expression. Mitochondrial homeostasis was maintained after silencing GADD45B via suppressing mitofusin 1 (MFN1) and mitofilin. The HIF‐1 signaling pathway was a downstream pathway of GADD45B, and its activation reversed the protective effects of GADD45B silencing on glutamate‐induced neuronal death, ferroptosis, and mitochondrial homeostasis. Silencing GADD45B attenuates epileptic neuronal death by inhibiting ferroptosis and maintaining mitochondrial homeostasis via inhibiting the HIF‐1 signaling pathway, which provides novel insights into epilepsy pathogenesis and potential biomarkers.