Ferroptosis Induction in Pentylenetetrazole Kindling and Pilocarpine-Induced Epileptic Seizures in Mice

Abstract

Epilepsy is a serious neurological disorder and is characterized by recurrent and unprovoked seizures. A critical pathological factor in the seizure genesis is neuronal loss. Until now, apart from the known regulatory cell death pathways, ferroptosis is a newly discovered type of cell death with the features of iron accumulation and the excessive production of lipid reactive oxygen species (ROS). In our present work, it was illustrated that ferroptosis occurs in murine models of pentylenetetrazole (PTZ) kindling and pilocarpine (Pilo)-induced seizures. In both of these seizure models, treatment with ferroptosis inhibitor ferrostatin-1 (Fer-1) efficiently alleviates seizures. This was achieved through elevated levels of glutathione peroxidase 4 (GPX4) and glutathione (GSH) as well as inhibitions of lipid degradation products including 4-hydroxynonenal (4-HNE) and malonaldehyde (MDA), iron accumulation, and PTGS2 mRNA in the hippocampus. It was concluded that ferroptosis is involved in seizure genesis in PTZ- and Pilo-treated mice, while the suppression of ferroptosis mitigates PTZ kindling, and Pilo-induced seizures in mice.

Lysyl oxidase promotes neuronal ferroptosis exacerbating seizure-induced hippocampal damage

“…Ferroptosis is activated in KA-induced seizure mice and human epileptic patients. Our prior work showed the presence of ferroptosis in various epileptic seizure models induced by chemical reagents including pentylenetetrazol, pilocarpine and FeCl 3 (22,23). To determine whether ferroptosis process was activated in KA-induced seizures, a common model resembling human intractable epilepsy, we detected a set of ferroptotic indices in the hippocampus of this model including morphological characteristics of mitochondrion, lipid peroxidation by-products including 4-HNE and MDA levels and Ptgs2 mRNA.…”

“…It is likely that seizure can initiate non-apoptotic forms of regulated cell death. Our recent work has delineated that ferroptosis, a novel cell death mode, is induced in FeCl 3 -, PTZ-and pilocarpine-induced seizure models (22,23). Similarly, in our current study, we also only provides a previously unknown cell death mechanism suggesting that ferroptosis is activated in epileptic seizures, but also strongly implicates that reducing ferroptosis is a valid therapeutic target for seizure-related disorders such as epilepsy, ischemic stroke, traumatic brain injury and Alzheimer's disease.…”

“…Total RNA was extracted using TRIzol reagent (15596018, Invitrogen, USA) following the manufacturer's instructions. The procedure of real-time PCR was conducted as previously described (22). The detailed information of primer sequences used in our study was summarized in Table 1.…”

“…Nowadays, ferroptosis has been extensively reported in multiple pathogenic conditions including cancers (17)(18)(19), neurological disorders (20,21) and renal failure (13). Particularly, our recent publications (22,23) have unequivocally proved the occurrence of ferroptosis in various chemical reagents-induced epileptic rodent models. And treatment with ferroptosis inhibitors (ferrostatin-1 (Fer-1) or liproxstatin-1 (Lipo-1)) efficiently alleviates seizures, highlighting a crucial role of ferroptosis process in seizure generation.…”

“…Future studies are essential to test the potential clinical implications of this therapeutic approach.MethodsEstablishment of KA-induced mouse seizure model and drug treatment. TheKA-induced seizure model was established as previously described with minor modifications(22). Briefly, the mice were deeply anesthetized and mounted on a stereotaxic apparatus (RWD Life Science Co. Ltd., China).A 5 μ l syringe (Hamilton, NV) was placed into the right dorsal hippocampus [anteroposterior (AP), -2 mm; mediolateral (ML), -1.8 mm; dorsoventral (DV), -2.3 mm] for KA injection (1.0 nmol of KA (Sigma-Aldrich, USA) in 1 μ l of saline).…”